Vehicle Train Routing Apparatus and Method

The present application is related to a patent application Ser. No. 195,279 that was filed concurrently herewith by D. L. Rush and entitled "Vehicle Train Tracking Apparatus and Method", which is assigned to the same assignee and the disclosure of which is incorporated herein by reference.

It is known in the prior art to provide an identification system on a train to enable the routing of that train moving along a roadway track. For example it is known for vehicle trains, such as operative with the BART system in San Francisco as described in an article published in December 1967 in Railway Signaling and Communications at pages 18 to 23, in an article published in March 1970 in Westinghouse Engineer at pages 51 to 54 and in an article published in September 1972 in Westinghouse Engineer at pages 145 to 151, to include a train identification system on every train that provides an identification to each station when the given train enters that station. It is known for vehicle trains, such as operative with the Seattle-Tacoma International Airport as described in an article published in January 1971 in Westinghouse Engineer at pages 8 to 14, to include a radio carried by every train to actively provide an identification to each station entered by that train.

The following publications relate to the equipment provided for the Atlanta Airport.

(1.) Atlanta Airport Automated Guideway Transit System by John Kapala for the ASCE Convention in Atlanta, Ga., Oct. 23-25, 1979.

(2.) Recent Applications of Microprocessor Technology To People Mover Systems by M. P. McDonald et al. for the IEEE Vehicular Technology Group Conference in Chicago, Ill., Mar. 28, 1979.

(3.) Atlanta Airport People Mover by T. C. Selis in the Conference Record of the IEEE Vehicular Technology Group Conference in Denver, Colo., Mar. 24, 1978.

The present invention is to be first applied to control vehicle trains in relation to the guideway transit system supplied for the Atlanta Hartsfield International Airport.

The present invention relates to determining the movement route of a vehicle train along a roadway track system from a location in relation to any station to any other station, where a route is found to be available depending upon operator inputs, the mode of operation and commands such as store and dispatch. A table of every available route in relation to each station and the known track plan is provided initially in a memory table. When a train arrives at a station, this table is used to establish the desired available route in relation to occupied track circuit signal blocks, the direction of train movement and gates cleared for the train to travel in relation to switches in the track system.

FIG. 1 shows a prior art physical arrangement of a typical track system;

FIG. 2 shows a schematic block diagram of a prior art vehicle train control apparatus;

FIGS. 3A, 3B and 3C show an illustrative track plan for the prior art track system of FIG. 1;

FIG. 4 shows the signal flow of a typical prior art routing apparatus;

FIG. 5 shows a prior art central control computer system block diagram, for controlling vehicle trains;

FIG. 6 shows a prior art control computer system block diagram for controlling vehicle trains;

FIG. 7 shows the typical digital input signals of the control computer system of FIG. 6;

FIG. 8 shows the typical digital output signals of the control computer system of FIG. 6;

FIG. 9 shows the sequential operations of a typical routing control system;

FIG. 10 shows prior art manual routing program routines and subroutines;

FIG. 11 shows a prior art manual cancel pushbutton routine;

FIG. 12 shows a prior art manual route cancel routine;

FIG. 13 shows a prior art manual setup pushbutton routine;

FIG. 14 shows a prior art manual route setup routine;

FIGS. 15A to 15M show prior art manual routing program tables;

FIG. 16 shows a prior art automatic routing program routine;

FIG. 17 shows a prior art route available routine;

FIG. 18 shows a prior art route select routine;

FIG. 19 shows a prior art priority route routine;

FIGS. 20A and 20B show a prior art route setup routine;

FIG. 21 shows a prior art route cancel routine;

FIGS. 22A-22M show the prior art automatic routine program tables;

FIG. 23 shows the station logic program in accordance with the present invention;

FIGS. 24A and 24B show the station entry logic routine of the present invention;

FIG. 25 shows the in station logic routine of the present invention;

FIG. 26 shows the station exit logic routine of the present invention;

FIG. 27 shows the ETC program routine;

FIGS. 28A and 28B show a prior art ETC program table setup for automatic routing;

FIG. 29 shows a prior art lockout table handling routine;

FIG. 30 shows the station lockout reset routine in accordance with the present invention;

FIG. 31 shows the trip stop lockout routine in accordance with the present invention;

FIG. 32 shows the run through detect subroutine in accordance with the present invention;

FIG. 33 shows the lockout cancel in turnback in accordance with the present invention;

FIGS. 34A and 34B a prior ETC program station cancel routine;

FIGS. 35A and 35B show the bypass flag handler routine in accordance with the present invention;

FIG. 36 shows a prior art FETCH subroutine;

FIG. 37 shows a prior art PACK1 routine;

FIG. 38 shows a prior art PACK0 routine;

FIG. 39 shows a prior art PKZ50 routine;

FIG. 40 shows a prior art PACK00 routine;

FIGS. 41A and 41H show prior art ETC program tables;

FIG. 42 shows a prior art interlocking track plan section;

FIG. 43 shows a prior art section of the track plan;

FIG. 44 shows the mode flag word in accordance with the present invention; and

FIG. 45 shows a prior art station status word.

The function of the train routing control is to route the trains around the system by establishing the desired available route for each train on the system from a presently occupied station to the next station, and to provide protection lockouts to prevent another train from requesting the same route or conflict with the movement of any other train, on a station-to-station basis.

For each of the stations in the track system, the present routing control has three separate operations, the first being the station entry logic which includes all logic necessary to process a train into a station. It is complete when a train runs through the station or when the train doors open. The second operation is the in-station logic, which involves next station determination and the route selection. It is completed when the route to the next station is selected. The last operation is the station exit logic, where functions are done to check the train out of a station when the heading and dwell time have elapsed, such as, closing the doors and sending information to the next station that the train has started and its train number.

In order to route trains around the system, the direction of travel must be known at the time a station becomes occupied. This direction for each track circuit is established by the above cross-referenced vehicle train tracking apparatus and method.

There is a gate signal in front of every switch for each direction of travel through that switch. Identification numbers are assigned to each gate signal, and these numbers are used to establish the desired routes. Exit and entrance tables are set up in relation to each gate signal location and are used to determine the route in relation to that gate signal. Each route has an associated information table which includes all physical conditions that have to be satisfied before a train is routed from that gate. When a route for a given gate signal number is found and stored, a check is made for other routes with the same entrance number and a determination is made to see which of these are available. If two exits are the same, there are two available routes and the priority routine is utilized to establish the desired one of these route for the train.

The train routing program is executed once each cycle for each occupied station to establish a desired route for the train that occupies that station.

FIG. 1 shows a prior art physical arrangement diagram of the new international airport complex now under construction in Atlanta, Ga. The main terminal 10 is at the west end. The international terminal 12 is north of the main terminal 10. Toward the each are four long narrow concourses 14, 16, 18 and 20 for the planes to load and unload passengers. Underground and running through the center from the terminal building 10 all the way up through concourse 20 is an underground transit system, including a first track 22 and a second track 24. To the east of concourse 20 is an underground maintenance area 26, which is large enough to store and repair transit cars. Normally, the passengers will come into the parking lots on either side of the main terminal 10 and go inside to the ticketing area, where they will obtain tickets and check baggage before going down to the lower area where the transit system is located to carry them to the proper concourse for catching an airplane. Coming back from one of the concourses, passengers ride an escalator down to the transit system and catch the next train for riding to the baggage area to pick up baggage and go up into the main terminal and leave.

The normal direction movement of the vehicle trains is counterclockwise. A typical train will start at station NG on the north track 22, and cross over through the switches to the south track 24 before stopping at south ticketing ST. The train then moves through stations SA, SB, SC and SD. At this point the train will reverse and cross over through the switches to the north track 22, stopping at stations ND, NC, NB and NA. The system can be set up to skip north ticketing NT and go to the baggage station NG. That is the normal mode of operation. It is desired that this system keep running regardless of most breakdowns or the like, so the computer control provides various backup modes of operation. Instead of using the turn back point in north baggage station NG, the train can go to south baggage station SG. On the east end, instead of using the south track station SD, the train can use south spur station SS, which is a pseudo station in the maintenance area 26 to the east of south track station SD, in case there is a switch problem on the crossover between the stations SD and ND. If there is a train broken down on either one of the north track 22 or the south track 24, there can be provided a shuttle mode, where a given train will go back and forth down each individual track 22 or 24 in shuttle fashion between any two or more stations on that track. For operation on off peak hours, one track can be shut down for maintenance and two trains can run on the other track using the bypass 28 for north track 22 and the bypass 30 for south track 24 to pass. There are twelve regular stations and four pseudo stations SY, NY, SS and NS. The pseudo stations are treated in the routing program like a regular station, except the doors can't open for a train stopped in a pseudo station. The pseudo station NY is located on the north bypass leg 28, station SY is in the south bypass leg 30, station SS is in the south spur on the south track 24 and station NS is in the north storage area which lies to the east of station ND between the two switches 32 and 34.

In FIG. 2 there is shown a prior art central control system 50, which can be located in a headquarters building and receives information about the transit system and individual vehicle train operation, and from a system manual operator 52 in relation to the desired performance of the individual vehicle trains. The central control system 50 supervises the schedule, spacing and routing of the individual trains. The equipment in the stations 54 is provided to operate with the central control system 50 as desired for any particular transit system. The wayside equipment 56 including track signal block circuits and associated antenna for speed command, door control and program stop control signals is located along the vehicle track roadway and is provided to convey information in relation to passenger vehicle trains travelling along the roadway track. A first illustrative train 58 is shown including three vehicle cars 60, 62 and 64 and a second train 66 including two vehicle cars 68 and 70. Each vehicle car includes an automatic train operation ATO and automatic train protection ATP apparatus to make up the automatic train control ATC apparatus. The automatic train control ATC apparatus includes the program stop receiver module, the speed code receiver module, the vital interlock board and power supplies and all the modules required to interface with the other equipment carried by the train vehicle, and in accordance with the more detailed description set forth in the above-referenced publications.

The interlocking subsystem 114 shown in FIG. 4 is a well-known apparatus that has been in operation for many years on rail transit systems. The function of interlocking is to prevent a train accident. The interlocking subsystem 114 is failsafe in operation and is constructed using failsafe relay logic. When a track circuit becomes occupied, a certain series of relays operates to block out another train from entering that track circuit. A failsafe signal transmitter and receiver operates with each track circuit to provide occupancy information which goes into the relay interlocking and is processed there, and the direction signal information results from it to indicate what direction the train is going over an area of track. The direction information is generated from interlocking based on the gate request, checking the occupancy of every track circuit in that area; checking opposing routes and switch positions, and so forth. If everything agrees, the gate clears, and the direction of traffic is set up, which direction of traffic is used to lock out opposing train moves.

The track system shown in FIGS. 3A, 3B and 3C has about 50 track circuits, and about 30 of them are covered by direction input bits as shown in FIGS. 3A, 3B and 3C. This specific version of interlocking has been in use for several years at the Sao Paulo switching yard in Sao Paulo, Brazil.

FIGS. 3A, 3B and 3C show an illustrative prior art track plan for the airport complex shown in FIG. 1. It is the layout of all the track circuits, switches and other equipment required to safely run the vehicle train system. The physical track includes the first track 22 and the second track 24, where the trains run. The rectangle boxes NG, SG, NT, ST, NA, SA, NB, SB, NC, SC, ND and SD represent the passenger stations, with the dotted area of the end representing space provided for expansion. Along each track, there are cross marks dividing the track into track circuit signal blocks 1T, 2T, 3T, and so forth. The track circuit 1T is to the left of station NG. The track circuit 2T encloses the station NG. Crossovers 100 and 102 are provided to the right of stations NG and SG, with each having two switch machines as required to move a section of track for passing a train from one track to the other track. The small brackets around each of switches and labeled A, B, C and D are gates or traffic signals. The direction of traffic is always into the face of the bracket. Every switch has a traffic signal or gate in front of it to inform the train when it is permissible to move through the switch. The small numbers 1, 2, 3 and 4 refer to the adjacent switch. Above and below the tracks are longer parallel brackets labeled TM followed by a number, and these are terminal zones; the trains are allowed to turn around in these zones, for example if a train enters a terminal zone going west it can reverse direction in that same zone and exit going east. These are train direction turn around locations. Above and below the track layout are direction signal areas that are used in the direction routine, such as 3-4E and 3-4W; if the E direction bit is a one, the train is going east, and if the W direction bit is a one, the train is going west. These direction bits are used to construct the DIR table, shown in FIG. 16B.

FIG. 4 shows the train routing signal flow of the present invention. The center block 110 shows the routing subsystem, which includes the programmed digital computer, the inputs and outpus to the computer and the several program routines and subroutines. At the left is the console and display 112. Information from the console 112 to the routing programs within the routing subsystem 110 are such things as train numbers and car numbers within each train so the routing subsystem can follow each of the trains around the track and determine when they arrive in stations. This routing subsystem 110 is different from those of the prior art, since there is no on board indentification or ID system. Once the train is put on the track system shown in FIG. 3 the tracking subsystem keeps track of which train it is and what cars are in the train. On the display portion of the console 112, there are facilities to display the train number, car number for any train on the system, by requesting this information with the proper pushbuttons and switches on the operator's console. The interlocking subsystem 114 checks to see if it is safe to allow the train to make a move, and provides for the vehicle safety of the system. The information required for the interlocking subsystem 114 includes the track circuit information, the gate status and the switch positions and is operative with the track circuits 116, the gates 118 and the switch machines 120.

The routing subsystem 110 requests actions from the interlocking subsystem 114 to allow the routing subsystem 110 to route each train around the track system. A primary input is from each station in regard to when the station becomes occupied or becomes unoccupied; these are two signals that the routing subsystem 110 uses to request a route for a train.

The information from the routing subsystem 110 is used to provide an alarm to the alarm subsystem 122, if a train does not open its doors or is late in arriving at the next station. The routing subsystem 110, when an alarm occurs, provides a message which is logged in the computer and is printed out on a typyewriter in the logs and reports 124, where it is entered into the daily log generated from this information. The routing subsystem 110 provides routes for each train on this track system from the time it enters until it leaves the track system.

FIG. 5 shows a prior art block diagram of the central control computer system 50 shown in FIG. 2. A console and display 150 is included, the operator inputs go into this console, with the status of the train system being shown on the display portion. The computer system 152 is described in more detail in relation to FIG. 6. The computer system 152 includes memory, input and output devices and the power supply. To the right of the computer block, the line printer 154 is used to print the reports and the teletype 156 is used to log all alarms and manual inputs, as they occur to provide a real time printout. The power system 158 controls the actual track power to the entire system, and includes relays and the inputs that go into the computer system 152 and to the console and display 150. The control of the power system 158 does not go through the computer, but is hard wired directly to the console and display, with the status of the system going through the computer to provide information for the printout. The interlocking and speed control equipment 160 is well known and had been provided in many train control systems to establish where each train is going, when it is going and how fast it is going to go. The station ATO equipment 162 is not associated with interlocking, and includes the non-vital relays associated with some of the control and part of the graphics. A graphics cabinet 164 is a relay cabinet which controls the graphics for signs at each of the stations. The radio system 166 can be a standard system which receives and transmits messages both data and voice to and from each of the cars on the system.

In FIG. 6 there is shown a prior art computer system 152 suitable for use with the present invention. A standard digital computer 175 can be purchased in the open market, for this purpose such as the LSI 2-20 from Computer Automation. It is a minicomputer provided with 32 K core memory. The selected options include a power fail interrupt that senses when the power drops below some certain level and provides orderly shutdown, a real time clock, a hardware boostrap loader in case it is desired to load a new program, a direct memory access channel to allow high speed data transfer, an interrupt system and various interfaces and controllers. The provided peripherals include a teletype, a paper tape reader, a paper tape punch, a floppy disc for program storage, and a line printer. The digital input and digital output systems are available from Computer Automation and convey information to and from the rest of the system.

FIG. 7 shows a suitable prior art digital input signal system 177, and each of the illustrated signals represents 16 input bits. The first line on the left is the function pushbuttons, which are on the operator's console. The second line contains the operation pushbutton inputs, which come from the operator's console. The third line is the location pushbuttons which correspond with the twelve stations and for pseudo stations shown in FIG. 1. The name for each line describes the particular inputs.

FIG. 8 shows a suitable prior art digital output signal system 179. There are two types of outputs on this system, TTL logic, which is used to drive the digital displays and relay contacts when there is a need for more power. Each of these output signals represents 16 bits of information. The name of each line describes the associated outputs.

FIG. 9 shows the representation of a typical control program, with the sequence of the different sections of the programming. The train control program in general uses a plurality of different routines most of which are per se prior state of the art logic. The first block 200 is initialization, which operates when power is lost or starting over for any other reason. The input routine 202 inputs the signals shown in FIG. 7 through TTL inputs as shown on these diagrams. They are input once each program cycle so that every routine within the program is using the same information. The output routine 204 is used to provide every desired output as shown in FIG. 8 each program cycle. The console routine 206 is a well-known routine to process the information from the operator to the computer, and vice versa; it handles all the pushbuttons, all thumbwheel switches, the digital displays, and so forth, and stores in memory whatever information is required for other sections of the program.

The ETC routine 208 takes inputs that were input from a previous routine and checks the values against previous values for the inputs respectively to see if any changes have occurred. It builds up a series of tables, a past value table, a change table, a went-to-one table, and a went-to-zero table. The routine 208 takes the input table and exclusive ORS that value with the past values. Any one is a change of state. There is a need to know which direction that change of state was, so comparing each change of state with the present values, establishes that it went to one which means the track circuit just became occupied, and it is stored in the went-to-one table. There is a need to know when indications clear so the routine 208 compares the changes with the past value, a one establishes that the bit just disappeared and went to zero. The table handling routine in the routine 208 does the same thing for track circuits, switch positions, gate indications, and pushbuttons; the alarm routine 210 uses this information. The alarm program 210 provides an alarm when switches don't move in time, gates don't clear in time, doors don't open in time, trains don't leave the station, trains don't arrive at a station, or trains run through a station. The tracking program comprises the direction routine 212 and the tracking routine 214. The next 16 blocks on this flowchart are the station programs 220 to be described in relation to FIGS. 23 to 41, which includes a route available subroutine 216 and a route select subroutine 218. Following the station program 220 is the route setup routine 222 which is a software interlocking type program which requests that any of the routes selected in the previous 16 stations are set up. It does this by requesting switch positions, monitoring the switch positions, and then requesting gates and locking out all opposing routes. The route setup routine 222 will be subsequently described. Next is the route cancel routine 224. Once a route is set up it will remain until manually cancelled or until a train takes the route, which is then canceled, track circuit by track circuit, as the train goes through, to provide a more or less equivalent operation to the well-known sectional release in the prior art hardware interlocking apparatus. The alarm logging 226 and report generation 228 are strictly the logging in memory of any alarm condition or operator action. This information is stored until it generates a report once a day such as at midnight.

The manual routing program is shown in FIGS. 10 to 15 and has two primary functions, both initiated by the console operator using the gate request pushbuttons. When the pushbutton is pressed, a gate request is made to open one of the gates shown in FIG. 3 and the manual routing program sets up the route from that gate over the switch positions in effect at the time. When the pushbutton is released, a gate cancel is made in relation to that gate and the manual routing program cancels the route from that gate. The automatic routing program shown in FIGS. 16 to 22 must know all routes which have been manually set up in order to prevent requesting an opposing or conflicting route. The manual routing program shown in FIGS. 10 to 15 fulfills this requirement by setting up all manually requested routes and setting the software lockouts for those routes.

Two routines and two subroutines in conjunction with the fetch and pack subroutines and tables comprise the manual routing program shown in FIG. 10.

The manual routing program allows the operator to set up and cancel routes from the console while the system is in the automatic mode of operation.

The cancel pushbutton processing routine 301 checks the PBCAN table once each program cycle. A route must be cancelled for each pushbutton indication which just went to zero. The manual cancel subroutine 305 is called once for each gate required, and uses the automatic routing tables 307 to cancel the route. The SR.sub.i tables are used to set zeros for switch position requests, gate requests, and lockouts.

The manual cancel PB processing routine 301 performs two major functions. In monitors the inputs from the gate cancel request table PBCAN 325, which contains the bits that require a route to be cancelled and acts as a bookkeeping routine for the manual cancel function. The PBCAN table 325 is processed through a software shift register to determine the bias of bits which are set. This bias is used on the PBENT table 329 to determine the entrance number associated with the pushbutton requesting a route cancel.

Each time a bit is detected by the shift register, the entrance number is located and stored in MCAN. The manual cancel subroutine 305 is then called to actually cancel the route. Each gate PB is checked each program cycle and every change from the one state to the zero state causes the associated route to be cancelled. When all bits in the PBCAN table 325 have been satisfied, control is transferred to the manual setup PB processing routine 309, which sets up manually requested routes.

The manual route cancel subroutine 305 is used to actually cancel a route which has been manually requested by the operator resetting the gate request push-button on the control console. The following items are zeroed or cancelled:

1. Lockouts

2. Switch position requests

3. Gate request

4. Route in ESTRT table

5. MSET, manual setup request.

The route entrance number found in MCAN is compared to the established route entrance in ESTRT 343 until a match is found. The keywords in ESTKEY 343 are then used to locate the proper setup information table (SR (i)) 307. The information words are used in conjunction with the PACKO 335 and PACKOO 337 subroutines to cancel the lockouts, switch requests and the gate request for the route. The route is then taken out of the established route table 343, ESTRT, ESTKEY and ESTTK. Finally MCAN is compared to MSET. If equal, MSET is set to zero.

The setup pushbutton processing routine 309 checks the gate indications went to one table once each program cycle. When a gate clears, its associated pushbutton input is checked. If the pushbutton is on, the route from that gate is setup over the switch positions in effect at the time. The manual setup subroutine 313 is called once for each route that is to be set up. The SR.sub.i tables 307 are used to determine which route is required and to set up the route.

The manual setup PB processing routine 309 is a bookkeeping routine which processes the PBSET table 323 and sets up routes as required. A manual route is required to be set up whenever a gate clears and the associated gate request PB on the console is pressed. The program acts after the fact. A route has actually been set up manually before the program is aware of it. This routine then sets up the same route and remembers it. Thus, the rest of the program is now aware that the route exists.

The PBSET table 323 is put through a software shift register to determine the relative position in the table for each bit in the one state. This bias is used to locate the gate entrance number from the PBENT table 329. The entrance number is stored in MSET and the MANSET subroutine 313 called to actually set up the route. One route is set up for each bit in the PBSET table 323 that is set. When finished, control is transferred back to the main control program.

The manual route setup subroutine 313 sets up the route that has been manually established by the operator pressing a gate request pushbutton on the control console. The entrance number of the route is stored in MSET. Since more than one route may have the same entrance point, this routine must determine which route from the entrance number is actually involved.

The entrance number is compared with the ENEX table 345 entrances until a match is found. The associated keywords in the KEYS table 345 tell where the route setup information table is located. The switch position words in the info table are checked to see if all switches in the route are in the requested positions. If any of the switches is not in position, this route is not the one desired. The ENEX table comparison is continued until another match is obtained and the new route info table located. Once again the switch positions are checked. This process is continued until a route with the MSET entrance number and all switches in the correct position is located. This route is the one to be set up by this subroutine, the ENEX, KEYS, and TKO pointers are all pointing to this route information.

Using the route information table; the switch request bits, the lockout bits and the gate request bits are set using the PACK1 subroutine 341. An open slot is located in the established route table (ESTRT) and the new route information is stored in ESTRT, ESTKEY and ESTTK. Now the rest of the program has the knowledge that the route exists. MSET is zeroed and control returned to the manual setup PB processing routine 309.

The manual routing program is based on tables including logic equations in those tables, with a small control routine that uses the tables. Table 323 is the PBSET table, and for each bit set in this table it is desired to set up a route. Table 325 is the PBCAN table, and for each bit set in table 325 it is desired to cancel a route. Table 329 is the PBENT table, which is the pushbutton entrance table, and for each one of the gate pushbuttons on the operator's console there is an associated route, so each gate has one entry number in this table. The table 323, the PBSET table, and table 329 and the PB entrance table, are operative with the manual pushbutton setup routine 309. The subroutine 331 is the fetch routine, which checks a given location in memory to see if a bit is set or not. The subroutine 335 is PACKO, it sets a specified bit to zero. The subroutine 337 is PACKOO, it sets two bits to zero. The subroutine 339 fetch routine is the same as subroutine 331. The subroutine 341 PACK1 sets a bit in a specified location in memory. The tables 343 ESTRT , ESTKEY and ESTTK are used by the subroutine MANCAN 305 and MANSET 313. The ESTRT table is a double word table, with the first word being the entrance location number and the second the exit location number. Assume a train is going from station north-baggage to station north-ticketing, which are adjacent. North-baggage has a number such as 100 and north-ticketing has a number such as 102, so this table would have the entrance number 100 and the exit number 102. The ESTKEY table is the keyword table, which is also a double word table, the first word contains the location in memory where the logic table pertaining to that route is stored; for example, there is a table for route 100 to 102 and it is located in memory location 1,000 and there are ten words in it. The second word in the keyword table tells the number of words in the table. The table ESTTK contains the location of the exit track circuit in the route, which is used to cancel that route. Each cycle the program checks the exit track circuit, and when it becomes occupied, the program cancels out all five of the associated numbers that are in the ESTRT table. Tables 345 are three individual tables, with the first one being the ENEX table. This table is a double word table, containing the entrance and the exit numbers of every possible route on the system.

These routes are based on a gate-to-gate arrangement, with each route reaching from one gate to another gate. The KEYS table contains the keywords for the setup table. There is one pair of words associated with each entrance and exit, indicating where an information table is located in memory and the number of words in the table. The TKO table, contains the exit track circuit for each route. The information from these tables is stored in table 343 after the route is set up. The table 307 is the SR.sub.i table, where i is the number of routes provided in the track system. There is one SR table for every route. Each word in each SR table points to one bit of information; the information in the word is the bit location in memory.

FIG. 11 shows the gate pushbutton manual cancel processing routine. The PBSET table is used to set up the routes, and gets processed in the manual setup routine shown in FIG. 14. Step 435 sets the pass flag. Since there are two word tables, this routine is executed twice. PASS is set equal to one which is equal to the index i. Step 437 sets PBIAS to zero, which is the bit bias in the input table. The routine takes the PBCAN words and shifts them through a software table. Each word in the table has sixteen possible bits in it so the PB entrance table has thirty-two numbers in it. The program is looking for a bit to be set, so it is necessary to shift until the program detects a bit. The P bias is used to go down into the entry table the number of shifts the program has made. At step 439 the shift counter is set to zero, which bit shift counter counts the shifts made until the word is complete. Step 441 checks to see if the first word of the PB cancel table is zero. If it is zero, go to 443 and add 16 to the bias, because there are sixteen bits in a word. At step 445 check to see if pass is equal to two. If the answer is Yes, the program is finished because it has processed both words. The first time it will be one. So at step 447 increment pass, and go back to set the shift counter equal to zero at step 439. Check to see at step 441 if there are any bits set in the second word of the cancel table. If a bit is set, from step 441 we go over to step 449. Increment the shift counter and at step 451 increment the bias, now the two counters are in position for this bit. At step 453 shift the word right one position and at step 445 check for an overflow. If there was an overflow the bit was set, and if there was not, it wasn't set. If there was no bit set the program goes back to increment the shift counter at step 449 and to increment the bias at step 451 and shift right at step 453. Taking the Yes case at step 455, there was an overflow. In step 457 save the contents of A register, since there may be another bit in the word. In step 459 the index L is set equal to PBIAS minus one, because at step 451 PBIAS was incremented before the bit was checked, so the counter is one count ahead of itself. This index is added to the location of the PB entrance table, to index into the PBENT table the proper distance and get the desired entrance number. At step 463 call the manual cancel routine shown in FIG. 12, which will cancel the route with that entrance number. At step 465 check the shift counter to see if it is equal to 16. If it is, the program is finished with this word go to step 445 and check if pass is equal to two. If it is, this is the second word and the program is finished. If it was not finished, do the second word. At step 465 if the shift counter was not sixteen, there may be more bits in the word so at step 467 reload what was stored at step 457. Go back up to step 449 and continue the process until the program is finished. This is a bookkeeping routine.

FIG. 13 is substantially identical to FIG. 11. The two routines are the same, except for checking to see which routes will be set up rather than cancelled. At step 603 of FIG. 13 the subroutine MANSET shown in FIG. 14 is called to set up routes rather than the subroutine MANCAN at step 463 of FIG. 11 to cancel the routes. Also step 605 of FIG. 13 cancels the bit being processed out of the set table, because it takes several passes through the program to set up a route.

FIG. 12 shows the manual cancel subroutine that is called at step 463 of FIG. 11. At step 501 set index register N equal one. At step 503 NMAX is set equal to the number of words in the ESTRT table 343. At step 505 a check is made to see if MCAN, the entrance number, is equal to the ESTRT table entrance number. If No, go to step 507 to see is N equal to NMAX and the operation finished. If the answer is No go to step 509 which sets N equal to N+2, since this is a double word table and the search is made on every other word. At step 505 a check is made to see if the entrance number equals the number now being found in the entrance table. If the answer is NO, go to step 507 and if N equals NMAX, go to step 511 and set SWFLG equal to zero and check at step 513 if MCAN equals MSET. MCAN is the number of the route to be manually cancelled. MSET is the number of a route in the process of being set up, so MCAN and MSET can be equal. At step 515 set MSET to zero. At step 517 set MCAN to zero and return. At step 505, when the entrance is found go to step 519 and set a new J index equal to one. This index is for the SR table, the individual route table. Step 521 sets WORD equal to ESTKEY sub N. The notation WORD means the location of a desired word/bit combination in that SR table. Step 523 sets JMAX equal to KEYWORD plus 1. Step 525 asks is WORD J less than zero. An indication word is negative and is less than zero. In an effort to determine which route is to be cancelled step 525 checks the switch positions and if every switch position in that route table is in the correct position, that is the route that is set up. In step 525 if the word is negative, which means it is a switch position indication, call the FETCH routine at step 527. Upon return check at step 529 to see if the bit was equal to one. If the answer is No, that is not the desired route so go to step 507 to see if the table is finished and continue the search loop. Assume the first switch position was correct, so go to step 531 and increment the index J by one to check the second word in the table. At step 525 is the second word negative and if the answer is Yes, call the FETCH routine at step 527 and see if the bit is one at step 529. If it is, go back to step 531 and check the next word. If there were just two switches in this route, the operation is finished since all the switches were in position so this is the route to be cancelled so in step 533 check is J equal to JMAX. The answer in this case would be No because the only words less than zero are switch positions and in a table that has 20 locations in it, only 2 or 3 will go to the step 527 because all the others are control words. The loop is finished with the whole table when J equals the maximum number. This is the route to be cancelled. In step 535 reset the table index to one. In step 537 get the address of the first word. At step 539 do the same thing that was done up in step 523, set the number of words in the table, and go to step 541 and establish if this word is less than zero. If the answer is Yes, again it means it is negative and therefore is a switch indication. If not, go to step 543 and check is the switch flag equal to one. There is a series of numbers in the SR.sub.i table which start off with positive numbers, then negative and back to positive. The first ones are switch requests, the next ones are switch indications and the next ones are lockouts. This switch flag tells which half of the table is being worked on. On first coming into the table the switch flag is going to be zero as it was set at step 511. For a new table, at step 541 the word J is not less than zero because it is started positive, so go to step 543 and check if the switch flag is equal to one. Again, the answer is No, go to step 545 and call PACKOO. For a switch machine there are two possible requests, a normal request and a reverse request, and arbitrarily it is desired to cancel both. The routine PACKOO sets both requests to zero. Step 547 checks if the operation is finished. If the answer is No, go to step 549 and increment the counter and go back to step 541 to check is the word J less than zero. It is probably going to still be No, since most routes have a couple of switches. Go to step 543 to check the flag equal to zero and go to step 545 and set zeros for the normal and reverse requests. At step 547 check if the operation is finished. If the answer is No go to step 549 and increment the counter again. At step 541, assume this time it is negative, the table is down to the indication words, so go to step 551 and set the switch flag equal to one. Go to step 549 to increment the counter. In the loop at step 541 check if the word is less than zero. If the answer is Yes, set the flag equal to one at step 551. It was already one, but set it again. Go to step 549 and get the next word. At step 541 check is it less than zero. Assume the answer is No, because now the search is below the indications. Go up to step 543 to see if SWFLG is set. The answer is Yes, because it was set in step 551. At step 553 call PACKO. Setting the flag at step 551 shows the operation is below the indication words in the table. Above the indications two zeros are set, in the indications nothing is set, and below the indications one zero is set. When the table is finished in step 555 the route in the ESTRT table is set equal to zero. At step 511 the switch flag is set equal to zero so the right sequence is followed the next time a route needs to be cancelled.

In FIG. 14 the program is similar to that shown in FIG. 12, and is the manual setup routine. This time instead of cancelling a route the program shown in FIG. 14 is going to set up a route.

At step 701 IMAX is set equal to 75, which is the number of routes in the transit system. Step 703 sets the index I equal to one. Step 705 checks if the entrance number MSET is equal to the first entrance location in the entrance/exit table. If the answer is No, this route is not the route to be set up. Step 707 checks if the table is finished. Go to step 709 and increase the index by 2 because this is a double word table. Go back to step 705 for each answer No continue around the lopp just described until the entrance is found. Go to step 711 and set up the same index loop similar to FIG. 12, by setting the J counter to one. Step 713 sets JMAX equal to the contents of KEYWORD plus 1, since this is a double keyword. Step 715 sets WORD equal to the contents of keyword. Step 717 checks if word is negative, by determining if it is less than zero. It should not be, since the table starts with positive words. Go to step 719 and check if the table is finished. The answer should be No, so go to step 721 and increase j, come around to step 717 and check if WORD is negative. At step 717 the first time a negative is found go to step 723 and call the FETCH routine to see if the switch was in position. If the switch is in position, at step 725 go to step 727 and increase the table index and continue. If the switch was not in position in step 725 this is not the route of interest. Go to step 707 and check if the entrance/exit table is finished. The answer should be No, so go to step 709 and get the next entrance and go through the loop gain. Eventually, the route will be found, if not step 729 is provided for the computer to come to a halt. From step 725, each Yes shows a switch in position, an increase of the index J at step 727 and check at step 717 if the new word is less than zero. For each No, go through the steps 719, 721 and 717 until getting to the bottom of the table. Then go to step 731 and once again reload the index and at step 733 reload WORD. The route is known that is to be set up. At step 735 check if WORD is less than zero. The answer is going to be no. So in step 737 call the PACK1 subroutine. The upper numbers in the table are switch position requests. Step 739 checks if the table is finished and the answer should be No. Go to step 741 and increment the index to get the next word. For each switch request step 737 operates once and then goes to step 741 to increment the index until all requests are finished. For each lockout step 737 will operate to set the lockout. When step 739 is complete the lockouts are set, the gate requests are set and the switch positions are set. It is now necessary to store this route in the ESTRT table, the established route table. At step 743 set the index N equal to one. At step 745 set NMAX equal to 31, which NMAX is the number of locations in the established route table minus one. In step 747 check if the first location in the established route table is equal to zero. The routes are not stored sequentially, they are simply stored in the first open slot. So step 747 checks if the first location in the table is zero, and the answer is probably No. So go to step 749 and check if the table is finished. The table is sized so it will hold every possible route so there should be no way to ever get to step 751. If it does, something has gone wrong and there is an illegal halt there. Again step 751 will be removed after checkout is completed.

In step 749 there is only one legal path, to step 753 to increase the index N by 2. Go back to step 747 and check is this location empty, and if the answer is No, make another loop. Eventually an empty slot is found in this table and the new route is stored in it. After finding an empty slot in the table, step 755 sets ESTRT.sub.n =ENEX.sub.i. The program was working on an I loop over the ENEX table, and the program was working on the N loop in the ESTRT table so step 755 takes the ENEX entry that was found earlier and stores it into the open slot of the ESTRT. The same thing is done in step 757 for the keyword and the same thing is done in step 759 for the exit track circuits. In step 761 set MSET equal to zero and the program operation is finished.

The automatic routing program performs four primary functions.

a. Checks if a route is available.

b. Selects the best path.

c. Requests the route from interlocking.

d. Cancels the route as the train takes it.

The several routines, subroutines, and tables shown in FIGS. 16 to 22 comprise this program. First, the program will be described functionally and then the path through the routines will be described. All routing is done on a station to station basis. At each station, the next station is determined and the route needed to get to the next station is established. Routes are automatically cancelled track circuit by track circuit as the train moves across them from station to station. Since the program must request all routes from the failsafe interlocking system, it is important to system operation that no route is requested which cannot be granted. To insure this function, the program has essentially been designed as a software interlocking system. The same conditions are checked by the program that are checked by the hardware interlocking system. This assures that no route is requested unless it is available.

The route available subroutine 800 shown in FIG. 16 performs all the checks necessary to determine whether a route is available. All routes do not have the same checks as others. Some have many of the same type of checks. The items to be checked for each individual route are contained in the available route tables (ARi) 802. Each word in each table is for one check. If every one of the checks in a route table passes, the route is available. Items checked are the following:

a. Track circuit occupied.

b. Track circuit software locked out.

c. Switch pushbutton in wrong position.

d. Wrong mode of operation.

e. By-pass mode flags set.

f. Trip stop in wrong position.

g. Station lockout set.

When a route passes all of its checks, it is available and is stored in the ENTAV table 804. It is possible that there is more than one path between the two stations. This is true for the by-passes and on the east end of the system. The route select routine 806 and the priority route subroutine 808 along with the associated priority table 824 are used to select the best path from one station to the next station.

The ENTAV table 804 contains every route available from the particular station used as the entry point. The route select routine 806 builds a route from the exit, forward to the entrance. The station exit number is compared to the routes in the available route table 804. If none compare, there is no route available from the entrance to the exit point desired. If the exit number appears in the ENTAV table 804 more than once, there is more than one path between the entrance and exit. The priority route subroutine 808 is then used to select the route with the highest priority. The route is stored in the ROUTT table 810.

After the route has been selected, the route setup routine 812 requests all switch positions and gates from the hardware interlocking. A specific sequence of events is performed.

a. Request the switch positions.

b. Wait until the switches are in the requested position.

c. Set the software lockouts.

d. Request the gates to the route.

The route setup routine 812 sets up every route that has previously been stored in the ROUTT table 810 by the route select subroutine 812. When the gate for the route clears, the route is taken out of the ROUTT table 810 and stored in the established route table (ESTRT) 814. The routes remain in this table until they are cancelled.

The route cancel routine 816 automatically cancels routes as they are taken by a train. Five separate functions are included in the route cancel routine 816.

1. Switch position requests and route requests are cancelled track circuit by track circuit as a train takes a route using the TKCAN table 832.

2. The route is cancelled from the Established Route Table (ESTRT) 814 when the exit track circuit 838 for the route becomes occupied.

3. Software lockouts LK 815 are TLK 817 cancelled when the associated track circuit becomes occupied. This function is done in the ETC Routine.

4. Switch position requests are cancelled when the switch position request pushbuttons are released.

5. Gate requests are cancelled when the gate request pushbuttons are released.

After a train takes the route, everything is in its quiescent state and ready for a new route to be setup as required by the train movement in the track system.

The route available subroutine 800 shown in FIG. 17 is called by the in station logic routine whenever a route is needed in order to get to the next station. This routine determines all possible routes from the selected entrance. Routes are unavailable because of through route limits, occupancy, opposing routes, conflicting routes, bypass flags, manual switch PBS, manual gate PBs, trip stops or incorrect mode. Each unit route has an associated entrance/exit table (ENEX) 818 location, a keyword table (KEYA) 820 location and a unit route information table 802. The entrance/exit table 818 is a double word table, the first word contains the entrance number and the second word contains the exit number. The exit word is negative when through routing is allowed and positive otherwise. The keyword table 810 is double word table. The first word contains the memory address of the unit route information table 802 and the second word contains the number of words in the information table 802. The unit route information table 802 contains the conditions that have to be met before the unit route is available. The LSTAR table 822 is an intermediate table which contains all unsatisfied entrances. An unsatisfied entrance is one which has not been checked with all of its associated exits.

The unit route information tables 802 contain the conditions that must be met for the route to be available; switch pushbutton requests for switches in the incorrect position, track circuit occupancy or lockouts which have been ORed together or incorrect mode. The program checks the bit position specified in each word in the information table 802. If the bit is zero, that condition is correct and the program goes to the next word. If the bit is a one, the route is not available. If each bit is zero, when the last word is checked, the unit route is available.

The program takes the initial entrance from the LSTAR table 822. The entrance is compared to the ENEX table 818. When a match is found, the same relative position is located in the KEYA table 820. This table contains the address and word count for the unit route information table. The entrance is set negative in the ENEX table 818 so it will not be used again and the unit route info table is used to see if the route is available. If not, the ENEX table 818 is searched for a different exit with the same entrance number. if no other exit exists, the entrance number is removed from the LSTAR table 822. If a different exit does exist, that route is checked for availability. This process continues until all exits from the given entrance are checked. Then the LSTAR table 822 is searched for a new entrance and the process repeated. When the LSTAR table 822 is zero, the search is complete. If a unit route is available, the exit is checked to see if through routing is permitted. If the exit is negative, the exit becomes the entrance for the next route and is stored in the LSTAR table 822. This process is continued until all unit routes which are available have been determined and stored in the ENTAV table 804. All entrances in the ENEX table 818 which had been set negative are set positive. The number of entries in the ENTAV table 804 is stored in KMX for use by other routines.

The available unit route table 804 is a working table containing the entrance and exit numbers for each unit route available from a given entrance. As conditions change the number of available routes tends to change. This table is loaded by the available route routine 800 when an entrance has been selected by the next station routine. The table is eliminated when the route has been selected by the route select routine 806. When an exit is selected, it is compared with the second location of this double word table to see if the exit is available. If it is, the route is selected and the table zeroed.

The route selection subroutine 806 shown in FIG. 18 selects the best path from the entrance station to the exit station. This route consists of unit routes extending from the entrance to the exit, which were in the available route table (ENTAV) 804. If more than one path is available, the priority route subroutine 808 determines the final path by utilizing the priority table 824 which lists the preferred path to each exit. The RTSEL subroutine 806 is called by the station logic program and executed if an entrance, an exit and unit routes in ENTAV 804 are present. The priority route subroutine 808 is executed anytime there are two or more paths from the entrance to the exit. The information required for this routine is: an entrance, an exit, all available unit routes stored in ENTAV 804 and the number of available unit routes (KMX). The information determined by the routine is a through route consisting of one or more unit routes stored in the proper station route table (ROUTT) 810 and the number of unit routes stored in MAXK.

The route is selected in the following manner. The station exit number is compaed to the exits of each unit route in ENTAV 804. If more than one unit route has the same exit number, the priority routine 808 determines which unit route to choose. The entrance of this unit route is compared to the station entrance. If they are the same, the route is complete. If they are not the same, the unit route entrance becomes the exit of some other unit route. This new exit is compared to the exits in ENTAV 804 as before. The process continues until the station entrance is reached. Each unit is stored in the proper station ROUTT table 810 as it is selected. When the last route is stored, the number of unit routes in the through route is stored in MAXK.

The priority route subroutine 808 shown in FIG. 19 is executed whenever the route selection routine 806 determines that more than one path is available from the station entrance to the station exit of the route being requested. The subroutine finds the proper exit in the PRIOR table 824 and then checks the route numbers below the exit in the PRIOR table 824 to see if they are available. The first route in the table which is available has a higher priority than any of the routes below it.

The priority of routes can be changed by changing the order of the number in the table 824. All priorities were chosen arbitrarily and can be changed if desired.

The route setup subroutine 812 shown in FIGS. 20A and 20B sets up the through routes determined by the route select subroutine 806. The information required by the routine is the number of unit routes to be set up (MAXK) and the entrance and exit number for each route which is stored in the ROUTT table 810. If MAXK has a number of routes to be set up, the routine is executed, otherwise control is transferred back to the setup control routine. Each unit route has an associated slot in the entrance/exit table (ENEX) 818, the keyword table (KEYS) 826, the exit track circuit table (TKO) 828 and a unit route setup information table (SR.sub.i) 830. The unit route setup info table 830 contains in order: the switch position requests for all switches in the unit route, switch position indications for each of the switches, lockouts for all conflicting routes, and the route request for the gate to the route.

The first unit route from ROUTT 810 is compared with ENEX 818, when a match is made, the same relative position in KEYS 826 gives the location and number of words of information in the setup info table. All switch position requests for the route are sent to interlocking. A through route is set up in reverse from the exit to the entrance. When all the switch positions in the last unit route agree with their requests, the lockouts are set and the route request sent. When the signal clears, the program goes to the next unit route. This process continues until the entire route is set up. At this time the route information; entrances, exits, key, key+1 and TK are moved to the established route table (ESTRT) 814. The ROUTT table 810 is zeroed and flags reset, and the route logic is complete.

The route cancel routine 816 shown in FIG. 21 performs automatic route cancel functions as a train takes a route. The routine 816 contains three sections. The first part cancels route requests and switch position requests whenever the track circuit in which they are located becomes occupied. This section of program uses three tables; TKCAN 832 is a table of all track circuits which contain a switch or a gate, KEYC 834 is a double word table containing the location of each cancel track circuit information table and the number of words of information in each, CKT(i) 836 contains one information table for each cancel track circuit. These tables contain the word/bit location of the request bits to be cancelled. The program searches the TKCAN table 832 for occupancies. Each time it finds one, the KEYC table 834 is used to locate the cancel information table 836 associated with the track circuit. Each word in the info table contains the bit location to be reset. The PACKO subroutine 839 is used to cancel the bit. The second pard of the routine 816 removes routes from the established route table (ESTRT) 814 whenever the last track circuit in the route becomes occupied. This is done by searching the exit track circuit (ESTTK) table 838. Whenever an occupancy is found, the route containing that exit track circuit is removed from the table.

The third part of the routine resets software lockouts as track circuits become occupied. Since the software lockouts LK 815 are ORed with the occupancies TKIN 813 to form the lockout table, the software bits may be removed when occupied, and the actual occupancy bits will cause the route to be locked out. The function of this routine is to cancel out a route, section by section, as a train progresses down the route. When the last track circuit in the route becomes occupied, the route is removed from storage.

The unit route entrance/exit table 818 is a double word table. The first location contains the entrance number of the unit route. The second location contains the exit number for the unit route. If the exit word is negative, throughrouting is allowed and the exit number becomes the entrance number for the next unit route.

The available unit route keyword table 820 tells the program where the unit route information table is located in memory. This table is a double word table. The first word contains the memory location of the info table. The second word contains the number of information words. The information in the keyword table 820 is generated by the assembler from label names on the first word of each information table 802. Each unit route information table 802 contains one label. The assembler assigns the label address of the individual information table to the first word in the keyword table 820. The address of the given information table 802 is subtracted from the address of the following information table to give the number of words in the table. This number is stored in the second word of the keyword table 820.

The unit route setup keyword table 826 tells the program where the unit route information table is located in memory. This table is a double word table. The first word contains the memory location of the info table. The second word contains the number of info words in the table. The information in the keyword table 826 is generated by the assembler from label names on the first word of each information table.

The unit route exit track circuit table 828 contains the input word location and bit position for each unit route track circuit. This table is used by the auto cancel routine 816 to cancel a unit route when the last track circuit in the route becomes occupied.

The unit route availability tables 802 are all used by the FETCH subroutine 840 called by the route available routine 800. Each word in these tables describes a specific bit location in memory. The right hand hex character contains the bit position in the word. The two center digits contain the memory location of the word. These tables are in fact logic equations. Each word contains one condition. All conditions must be satisfied before the route is available.

The unit route setup tables 830 are used by the FETCH 840 and PACK subroutines 839 and 842 called by the setup and cancel routines. Each word describes a bit location in memory and contains a flag to tell the program whether to set, reset or check the status of the bit. The left hand hex digit is an 8 if the word is a switch position indication, otherwise it is a 0 and the word is a control word.

The SR(I) tables 830 are divided into three sections, switch position requests, switch position indications, and lockouts and route request. The last word in each unit route table 830 contains the route request for the route. The words in the first section are positive, the second section negative, and the third section positive. This allows the program to keep track of which operation is required.

A route is cancelled using the same tables 830. The first section of the table contains switch position requests. These requests are cancelled using the PACK0 subroutine 839. The second section of the table is ignored because it is used for indications only. The third section contains lockouts and the route request. These bits are cancelled using the PACK0 subroutine 839.

The track circuit table (TKCAN) 832 is used by the automatic cancel routine 816 to determine when a track circuit which contains switches or gates becomes occupied. When the circuit becomes occupied the switch position requests and the route request are set to zero.

The cancel keyword table (KEYC) 834 tells the program where the auto cancel track circuit information table 836 is located in memory. The KEYC table is a double word table. The first word contains the memory location of the info table. The second word contains the number of info words in the table.

The track circuit cancel information tables CKT(I) 836 are used by the PACK0 subroutine 839 which is called by the auto cancel routine 816. Each word in these tables describes a specific bit location in memory.

FIGS. 17, 18, 19, 21A, 20B and 21 are all prior art routing program flow charts and FIG. 22 shows the tables used by the routing routines. These figures will not be described block by block because they are prior art. A brief description of the figures will be given.

FIG. 17 shows the prior art Route Available Routine flow chart. This routine performs a software interlocking function of determining whether a route is available or not. This routine is called by the In Station Logic Routine, FIG. 23, 1402, whenever a route to the next station is required. The AR(I) tables, FIG. 22, are used to determine whether the route is available or not. Each route has an associated Available Route (AR) table. The table contains one word for each condition which may cause the route to be unavailable. If none of the conditions specified in the AR(I) table exist, the route is available for use by the Station Program. When this routine returns to the Station Program, all available routes have been stored in the ENTAV table.

FIG. 18 shows the prior art Route Select Routine flow chart. This routine selects the path from one station to the next station from available routes stored in the ENTAV table. This routine is called by the In Station Logic Routine, FIG. 23, 1402, whenever the Route Available Routine has returned with available routes stored in the ENTAV table. The route selected by this routine is stored in the proper station ROUT table. If more than one path is available, the preferred route is chosen by the Priority Route Subroutine, FIG. 19.

FIG. 19 shows the prior art Priority Route Subroutine flow chart. This subroutine is called by the Route Select Routine whenever more than one path is available between stations. A Priority table PRIOR is used to determine the path with the highest priority. When the best path has been determined this routine returns to the Route Select Routine.

FIGS. 20A and 20B show the prior art Route Setup Routine flow chart. This routine requests the routes, which have been selected by the Route Select Routine and stored in the individual station ROUT tables, from the hardware interlocking equipment. This routine is executed once each program cycle for each station that has a route pending. Switch position requests are sent to interlocking. Switches are then monitored until they are in the requested positions. Route lockouts are set and the route request is sent to interlocking. The gate is monitored until it clears. The route is then removed from the ROUT table and stored in the ESTRT table where it remains until cancelled.

FIG. 21 shows the prior art Route Cancel Routine flow chart. This routine cancels a route as the train goes through the route on a track circuit by track circuit biases. This routine is executed once each program cycle. Whenever a track circuit which contains a switch or gate becomes occupied, the switch position requests and gate requests are set to zero. When the last track circuit in the route becomes occupied, the route is removed from the ESTRT table. The lockouts are cancelled whenever the track circuits associated with the lockouts become occupied.

FIG. 22 shows the prior art tables used by the routing routines, FIGS. 17-21. These tables have been described in the FIG. 16 description.

The station logic program of the present invention shown in FIG. 23 consists of three routines:

a. Station Entry Routine shown in FIG. 24

b. In Station Routine shown in FIG. 25

c. Station Exit Routine shown in FIG. 26.

Each of the stations and pseudo stations has these three routines plus associated tables. Only one set of flowcharts is provided since it is believed that each station program in view of the disclosures of FIGS. 23 to 26 would be obvious to persons skilled in this art to provide additional station programs by routinely modifying the disclosed station program to fit the necessary conditions for another particular station. Some stations have run-throughs and some do not. Some stations have approach blocks from both directions, while some have them from one direction only. Some stations have turnbacks from one side, some have turnbacks from both sides, and the pseudo stations don't have turnbacks with the exception of South Spur. Trains may be stored in certain stations and not others. Trains may be dispatched from those stations where they may be stored. Routes are required between some stations and not required between others. All these variables are taken care of in the individual station logic routines.

The station logic program shown in FIG. 23 performs all the necessary functions to check a train through a station. The primary function is to determine the next station and to clear a route, if required, to that next station in time so that the train will not have to slow down or stop in front of a gate that has not cleared. A secondary function is to regulate the spacing of the trains on the system. Dwell times, headways, and available paths to stations are some of the conditions that are used for the spacing function.

Two different series of operations are required, depending on whether or not a run-through is in effect. For the run-through case at least one approach track circuit on each side of a station is used for a reference point where the status of the out of service pushbutton on the operator's console is checked. If on, the program proceeds to set up a route to the next station. This allows time for the route to clear before the train gets to the gate. At the time the station track circuit becomes occupied, the train is checked out of the station by starting the headway and train late clocks and sending the train length and train number to the next station. The run-through alarm flag and the no depart to alarm flag are set for the next station. The run-time to the next station is determined and stored in the RUNTIM table.

For the station stop case, the program checks the train into the station when the station track circuit becomes occupied. The program then waits until the doors open. At this time a computer requested hold train with doors open HTDO output is set, and the dwell time clock is started.

While the train is waiting for the dwell time to elapse, the program determines the next station. This involves a desired direction of travel, where the train is located, out-of-service pushbuttons, turnback pushbuttons, and mode of operation. As soon as the next station is determined, a route is selected to that station if one is PG,41 available. This route is then established by hardware interlocking.

When the route is selected, the train is now ready to be checked out of the station if all conditions permit. Several things must be satisfied; the dwell time must have expired, the headway time must have elapsed, the track to the next station must be clear of traffic, manual hold, HTDO, and recycle doors pushbuttons must not be on, and the gate for the route must be clear. When all these conditions are met, the train is checked out of the station. The close door command is sent, the HTDO output bit is reset, the headway clock is started, the train length sent to the next station, the train number is sent to the next station, the run time is sent to the next station, the run-through alarm flag for the next station is set, the no depart to alarm flag is set and the train late timer for the next station is started. The train leaves the station and the station program is finished until the next train arrives.

The station entry logic program checks a train into a station or through a station if it is going to run through it. The in-station logic program performs all the functions that are required while the train is in a station during the provided dwell time to set up the route for the train to travel to the next station. The station exit logic program checks the train out of the station and sets up the next station for the train. Each of these programs is operationally related to the train positional space on the system rather than time. There are 16 stations in the track system shown in FIG. 3, and includes 12 real stations with passenger doors and four pseudo stations. The pseudo stations are in the two bypasses, at the north storage area and in the south spur. The program does not know the difference between a pseudo station and a real station.

In FIG. 23, there is shown the overall station logic program block diagram of the present invention, including the above three program routines, the station entry routine 1400, the in station routine 1402, and the station exit routine 1404. The in station routine 1402 is involved with the routing functions. Whenever a route is required to the next station the route available subroutine 1406 is called. In addition there is called the route select subroutine 1408. If a route is available the route select subroutine 1408 actually selects a particular path that the train will travel. If there is more than one path available, the route select routine 1408 has to call the priority routing routine 1410. The station entry routine 1400 operates with the dwell clock table 1414 which provides one second clocks used to determine the dwell time a train will be in the station. At the time the doors open the dwell clock is started for the station and counts continuously. The station exit routine 1404 will check to see how long the train has been in the station and after the desired dwell time has elapsed will release the train. The MAXK table 1416 contains the number of routes that are to be set up from the station. Due to the addressing structure on the Computer Automation machine 175 shown in FIG. 6 indirect address pointers are required, so the station entry routine 1400 sets up the indirect pointer for the address of this table 1416. The route table 1418 is a table in memory which contains the numbers of the entrances and the exits from a given station. The in station logic routine 1402 sets up the ROUT table address pointers for the rest of the routines to use. The station status word table 1420 has one word for each station. Each of the 16 bits in the word (FIG. 45) has one piece of information about the status of the program operation concerning that station. For example, when a train comes into a station the status word is zero, when the station track circuit becomes occupied a one bit in this word is set. As soon as the station is occupied, the station entry routine 1400 starts looking for the doors to open and goes into a holding pattern. When the doors open, the door open bit is set in the status word 1420. This word is continuously processed until the last bit is set indicating that the station exit logic is complete and the program now bypasses the station logic program until the status word is cleared. The station exit routine 1404 utilizes the dwell clocks 1414. The clock was set by the station entry routine 1400 and is checked in the exit routine 1404, to see if the dwell time has elapsed. The headway clocks 1424 are another set of clock used to determine train separation, derived by taking the run time plus the dwell time and dividing it by the number of trains on the system. The headway clock 1424 is set to zero when the train leaves a station. The next train has to wait the desired headway time before it is allowed to leave that station. The train late clock 1426 is used for alarms; this clock is set to zero when the previous station exit routine is complete. The alarm programs check to see if certain events have occurred. The first check is, has the station block became unoccupied? If within 30 seconds the occupancy does not go away, an alarm is given. If the doors do not open at the next station within a set period of time an alarm is generated. The dwell time table 1428 provides dwell times adjustable by the operator from the console, each station is individually selectable. The table 1428 contains the number that the operator has entered. The STRLOC table 1430 contains the TRLOC location for the particular station. The TRLOC table was described in the tracking program covered by the above-referenced related patent application. It contains the train number of the train in each track circuit. The TRNO table 1432 is the train number table and contains the numbers of the trains on the track system. The TRLEN table 1434 is a train length table and contains the number of cars that are in each train. These two tables are used by the station exit routine 1404 because the train length is required to be sent ahead to the next station so the passengers know which doors are going to open. The station exit routine 1404 takes the train number from the STRLOC table 1430, uses the train number to get the relative position in the TRNO table 1432 and from the same relative position in the TRLEN table 1434 determines the length, and then sends the length to the next station graphics to operate the correct number of signs over the doors.

The station routine entry NMELOG shown in FIG. 24 performs the functions required to check a train into a station. There is one program for each of the stations. An approach track circuit on each side of each station is used as a detection point, where it is determined whether a station run-through is in effect. If a run-through is in effect, a flag is set and control transferred to the in station routine shown in FIG. 25. Otherwise, the train is checked into the station and when the doors open, the dwell clock is started, a computer HTDO is set and control is transferred to the in station routine.

When the routine is entered, the station entry complete flag is checked to see whether the entry logic is complete. If not, the station occupied flag is checked to see if a train has been checked into the station. If the flag is set, the program checks, once per cycle, to see if the doors have opened. When the doors open, the computer HTDO outut bit is set, the station HTDO flag is set, the door open flag is set, the dwell time clock is started, the dwell start flag is set, the entry complete flag is set and the program jumps to the in station routine. If the station occupied flag was not set, the approach track circuits on each side of the station are checked for occupancy. If either of them becomes occupied, the direction of travel is checked to see if the train is coming into the station. If the train is not coming into the station nothing is done. If the train is traveling toward the station, the station out of service pushbutton is checked. If off, nothing is done. If a run-through is in effect, the run-through flag is set, the entry complete flag is set and control transferred to the in station routine. If no approach track circuit is occupied, or if the trains in them are leaving the station, the station track circuit is monitored for occupancy. As soon as it becomes occupied, the station occupied flag is set. A special case is invoked if a train is being stored in a station that has doors, such as at North and South Baggage. When the dwell timer is started, a check is made to see if the train is to be stored in the station. If not, the normal path is taken. If it is to be stored, the normal dwell time is used to maintain the open door period and then the doors are closed. The logic then ignores the train until a dispatch train command is issued by the operator.

FIGS. 24A and 24B show the station entry logic for a typical station. At step 1450 get the status word, which has 16 individual bits to denote the status of the processing of the train through a station. In step 1451 check if the entry logic is complete. If yes, this routine is finished, go straight to exit 1452 which goes to the in station logic shown in FIG. 25 as compared to the exit 1453 which goes back to the main program shown in FIG. 9. From step 1451 if the answer is no, go to step 1455 and check if the occupancy flag is equal to 1. If no, go to step 1457 and check if the east approach track circuit is occupied. Step 1458 checks if the west approach track circuit is occupied. At step 1457 if Yes, check at step 1459 what direction the train is going. The train could be leaving the station rather than coming into it, so if the east approach circuit is occupied at step 1457 then check is the direction east at step 1459, and if the answer is yes the routine is not involved because this is the approach circuit on the east and the train is moving east so it is not coming into this station. The same type of checks are made using steps 1458 and 1460 to check if the west approach track circuit is occupied and is the direction west. Again, if the answer is No, the train is not coming into the station, so go to step 1462. If in either step 1459 or 1460 the train was coming into the station, it is desired to set direction flag bits. At step 1459 is the direction equal east, if No, at step 1463 set the direction flag equal to 1, because the train is going west. At step 1460 is the direction west, if No, go to step 1464 and set the direction flag equal to 0. Steps 1465 and 1466 check if the operator's run-through button has been pressed, and if the answer is no, go to step 1462 and mark time. In both cases if the run-through button is on, go to step 1467 and set the run-through flag bit in the status word. Go to step 1468 and reset the run time, which run time was set in the run time table at the previous station in relation to checking whether there is a train late alarm. Since the train is not going to stop at this station there is no need for an alarm. In step 1469 reset the run-through alarm flag. In this particular case the train is going to run through the station so the alarm is disabled. In step 1471 set the entry logic complete flag to avoid going through this routine again. In step 1472 save the status word, so it is available again next cycle, and go to the exit 1542, the entry logic is complete. If there is no run-through in effect at steps 1465 and 1466, if the train is going in the wrong direction, or if the approach blocks were not occupied, go to step 1462 to check if the station track circuit is occupied. If the answer is No, go to the exit 1453, this is the mark time exit. In the next cycle at step 1462 check is it occupied, when Yes, go to step 1473. The series of steps 1473, 1474 are to determine the direction and to set it for the rest of the routines. Step 1473 checks if the direction is east, if Yes go to step 1474 to set direction equal to 0 and if No go to step 1475 to set the direction equal to 1. At step 1476 check if the closed door pushbutton is on. If on, the doors will not open. If yes, go to step 1477 and reset the run time, so there will not be an alarm because the door failed to open within a certain period of time. At step 1478 set the occupancy flag bit in the status word, at step 1479 save the status word and go to exit 1453. This exit is to the main program in FIG. 9 because this program logic is not finished.

At step 1455 check if the occupancy flag equal to 1, and assume the answer is Yes. At step 1481 check if the dwell timer has been started, the answer is no, because the doors haven't opened. Step 1482 checks are the doors open yet. The answer is going to be No, since the doors are not open yet. Go to exit 1453 and mark time. When the doors open, at step 1482 go to step 1483 and set the HTDO bit. Go to step 1484 and start the dwell timer. At step 1485 set the hold train doors open flag, it is set is to monitor progress. Go to step 1486 and set the door open flag in the station status word. At step 1487 set the dwell started flag, which is also in the station status word. Now go to step 1488 and check if the stored train flag is set, which means the train is stored in the station. If it has been stored, it is going to sit there until dispatched. For the normal case, the flag is not set, so go to step 1468 and go out through the path to exit 1452 which was described before. If the stored train flag was set, go to step 1489 and check the manual dwell time. There are both manual dwells and automatic dwells in this system. If the operator has failed to enter a dwell time for a station, there is a dwell clock inside the logic cabinets for each of the stations. If there is a manual dwell time, the computer has no idea when the clock is going to expire. Assume the control is not in manual, go to step 1491 and check if the dwell has expired. If it has not expired, go to the exit 1453 and mark time until it does expire. Then go to step 1492 and close the doors. Go to step 1493 and reset the hold train door flag, and go to step 1494 and reset the actual hold train doors open command. Then go to step 1468 and complete the logic.

Back at step 1489 check the manual dwell, if the operation is in manual dwell there is no need to check the dwell time or close the doors, because they will be closed by the manual dwell clock. From step 1489 go to step 1493 and reset the two flags and go to exit 1452. This is the only case when a dwell time is checked in the station entry logic. When a train is stored in the station, it will stay there until it gets a dispatch command. However, if the train is being stored in the station, it is desired to come into the station, perform the normal dwell so the people can get out and then shut the doors and leave it there.

The function of the in station routine NMILOG shown in FIG. 25 is to clear a route to the next station during the dwell time of a train in the station or while the station is being run through. The direction of travel is determined. The next station is determined. The routine then calls the route available and route select subroutines. Control is then transferred to the station exit routine.

The in station routine performs all functions required to set up a route to the next station. An integral part of this routine is to determine the direction of travel and the next station in the route. When the routine is entered, the MODE flag is checked to see if any mode of operation is in effect, if not this routine is bypassed. Next, the dispatch flag is checked to see if a train in this station is to be dispatched. Then the INROUT word is checked to see if the station is in the route. If yes, the in station complete flag is checked to see if the in station logic has been completed. If not, the direction of travel is determined based on gate status, traffic indications and turnback pushbuttons inputs. The DIR flag is then set.

The next station is then determined from the direction of travel, mode of operation and present station location. The next station ENTR and EXIT numbers are stored for use by the routing routines. The proper status flags are then set.

The route selected flag is checked to see if a route has already been selected. If not, the flag is set for those stations which do not require a route to be set up to get to the next station. If a route is required, the pointers for the ROUTT table and MAXK table are stored for use by the routing program. The route available routine is now called. A check is made of KMX, the number of available routes, to see if any routes are available to the next station. If not, this routine is exited and another try is made the next program cycle. If available unit routes were found, the route select routine is called to select the path to the next station. MAXK is checked to see if a route was actually selected. If it was, the route selected flag and the in station complete flag are set and control transferred to the station exit routine. If no route was selected, the program will attempt to find a route the next program cycle.

FIG. 25 is the in-station logic, which does all functions required while the train is in the station. The routine operates as soon as the station entry logic shown in FIG. 24 is complete, a train is in the station with its doors open a run-through is in progress or the train has been stored previously. At step 1600, check if this track in one of the operating modes. If the occupied station is on the south track, the routine will check the south track bit, and if the station is on the north track, the routine will check the north track bit. If the answer is no, this track is not in an operating mode, the routine goes to step 1602 and exits. This routine has two different exits just like the previous one. The exit number 1602 is a mark-time exit, and goes back to the main program. Exit number 1604 is only used when this in-station logic is complete, and from that point it goes to the exit logic program in FIG. 26. If this track is in an operating mode, go to step 1606, and check if a train is being dispatched. If the answer is no go to step 1608 to check if the stored flag is set. This flag would be set when a train has been stored in the station. Step 1610 checks if this station is in the route. If this station is not in the route, go to exit 1602 and wait. At step 1610, if the station is in the route, check in step 1612 to see if the in-station logic flag is complete. If the answer is no, go to step 1614 to determine if the direction-determined flag has been set. If the flag is not set, at step 1616 determine the direction by checking the DIR table. At step 1618 store that direction bit in the DIR flag bit. At step 1620 set the flag that indicates the direction has been determined so the program will not go through the check again. At step 1622, which is the same place that the program would have gone if the flag was already set to one, check to see if the next station has been determined flag is set. At step 1624 check the direction if required. For end point stations this check is not needed because the train can only go one direction. Step 1626 checks the mode flags, this involves the mode flag word shown in FIG. 44 to see which of these specific bits is set to find out where the train should go. As a result of the direction that the train is going as determined in step 1624, the mode that the train is operating in determined in step 1626, go to step 1628 and determine what the next station is. Step 1624 checks if there is a turnback in effect and if that button is pressed, the train leaves in the direction it entered. Step 1630 stores the bias pointer for the next station. The selection of the next station in step 1628 includes selecting a bias for that station. At step 1632 store the entrance number into a location called ENTR. In step 1634 store the next station exit number. This provides a route definition such as 100 to 108 and is used by the route available routine. Step 1636 zeros KMX, which is the number of routes that are available from the entrance. Step 1638 sets the next station determined flag to prevent going through this loop again. Step 1640 determines if the route selected flag has been set. Step 1642 checks if a route is required. There are several stations with no gates between them and the next station and no route is required. If no route is required, go to step 1644 to store the route selected flag. If a route is required, go to step 1646 to set up pointers for the tables that store this information. For each individual station the routes are stored and then at the completion of all 16 stations, the set up control program sets up all routes. The steps 1646 and 1648 set up addresses as to where this invention is to be stored. Step 1650 is the call to the route available subroutine, which determines whether there are routes available by going through the proper tables. When the program returns, step 1652 checks does KMX=0, with KMX being the number of routes that are found. If KMX is 0, there is no route available, and the program goes to the exit 1602 and marks time until next cycle through the program. When a route becomes available, go to step 1654 to call the route select subroutine. There are routes available and now the program selects the route including any priority that is required. Step 1656 checks if MAXK is equal to zero, if the routine found a route from the entrance to the exit, it will not be 0. If the answer is yes, mark time by going to step 1602. From step 1656 as soon as there is a route available, there is a number in MAXK, which number is the number of unit routes. In step 1656 when a route is found, go to step 1644 to set the route selected flag. Go to step 1658 to set the in-station complete flag, and exit at step 1604 to go to the station-exit logic.

The function of the station exit routine NMXLOG shown in FIG. 26 is to check a train out of a station after the dwell time and heading time have elapsed, the track is clear to the next station, a gate is clear, and no manual over-rides are in effect. The train late timer for the next station is started, the train length is sent to the next station, the train number is stored for the next station, the run-through and no depart to alarm flags for the next station are set, and the run time to the next station is determined and stored in the RUNTIM table. In the run-through case, the only functions performed are the train late timer and train length for the next station sent and the alarm flags are set.

The station exit routine performs all functions required to check a train out of a station. Two separate cases are involved, a normal station stop and a station run-through. When the routine is entered, the station exit complete flag is checked to see if the station exit logic has been completed. If not, the run-through flag is checked to see if a run-through is in progress. If yes, the station block occupancy is checked to see if the train is present. The program marks time until the station block becomes occupied. This is necessary because the train length and other information must be determined and sent to the next station. The STRLOC table contains the TRLOC table address for each of the station track circuits. When the station track circuits become occupied, the STRLOC table is used to determine the TRLOC table location for the given station. The train number is then obtained from the TRLOC table. This train number is then compared to the TRNO table which contains the train number of all trains on the system. The TRNO table bias is then used to determine the train length from the train length table, TRLEN. This train length is sent to the next station to be used in the graphics logic. The headway timer in the present station and train late timer in the next station are started. The station exit complete flag is set and the routine is complete. If no run-through is in effect, the normal check out of the station sequence will be executed. First, the headway complete flag is checked. If not set, the program monitors the headway clock until it equals the headway time. When the headway time has elapsed, the headway complete flag is set. Next, the dwell complete flag is checked. If not set, the program compares the dwell time in effect with the dwell time clock until they are equal. When the desired dwell time has elapsed, the dwell complete flag is set. At this point it is time to release the train if conditions permit. The occupancies between the present station and the next station are checked to ensure no train is present. A train cannot be released from a station until it has a clear track into the next station. When the track is clear, the route cleared flag is checked. If not set, the program monitors the gate for the route until it clears. The route cleared flag is then set. Three manual pushbuttons must now be checked: manual hold train with doors open, HTDO; manual hold, hold; and manual recycle doors, RCYCLE. If any of these pushbuttons is pressed, the program marks time. When all three of these pushbuttons are off, the train is checked out of the station.

The door close signal is sent, the HTDO bit is reset, the headway timer started, the train length sent to the next station, the train late timer in the next station is started, the run time to the next station is obtained from the ERUN or WRUN tables and stored in the RUNTIM table slot for the next station. This value is used to determine the no arrive at alarm. The no depart to alarm reset bit is stored in the RBIT table, the run-through and no depart to alarm flags are set for the next station, and the station exit complete flag is set.

FIG. 26 shows the station-exit logic, which routine checks the train out of the station and sends whatever information is required ahead to the next station.

Step 1700 checks if the exit logic is complete, and if it is, goes to step 1702 and the program is finished. If it is not, step 1704 checks if there is a run-through in effect at this station. If there is a run-through in effect, the train is not going to stop but still requires the sending of information ahead to the next station. Assume a run-through, go to step 1706 and check if the station is occupied, until the station becomes occupied, the program does not know which train it is. If the station is not occupied, go to exit 1702 and mark time. At step 1706 the program will wait until the station track circuit becomes occupied, and then look into the tables and find out which train it is and get the train length and number. When the station becomes occupied, go to step 1708 and check out of the station. The program goes through the steps from 1708 to 1736, which is the checkout list covering things required at the time the train is leaving. At step 1704, when there is no run-through, go to step 1740 to check if the doors on this train are open. The doors are supposed to be open at the time this routine executes because the train is performing a dwell, so under the normal case, the doors will be open. However, the operator has a button on the console to close the doors, and the operator can close the doors when the train is in the station. If the doors are closed, the train is going to leave, go straight to step 1708 and check the train out. If the doors are still open, go to step 1742 to check if the track is clear to the next station. A train cannot leave a station unless the path is clear all the way up to and including the next station. If the answer is no, go into a holding pattern to the exit 1702. If the answer is is yes, check at step 1744 if the route-clear flag is set. If this flag is not set, go to step 1746 to check if the gate is open, and if it is not, go to step 1702 and wait. If it is open, set the flag at step 1748 and go to step 1750 to check if the headway-complete flag is set. If not, go to step 1752 and check to see if the desired headway has elapsed yet. If the answer is no, go to step 1702 and wait. If yes, go to step 1754 to set the headway-complete flag. Step 1756 checks if the dwell-complete flag is set, if not, go to step 1758 and check if the dwell is manual. If manual, there is no control over it. If no, go to step 1760 and check if the dwell time has elapsed. If the answer is yes, go up to step 1762 and set the dwell-complete flag to 1. If the answer is no, go to step 1764 to check if the minimum dwell time has elapsed. If the answer is no, exit to 1776 and wait. If the answer is yes, set the dwell-complete flag at step 1762. At step 1758, if the manual dwell time is on, the program has no control of the doors, so go to step 1768 and reset the hold train doors open output bit that was set when the doors opened. At step 1770 check if the doors are open and if they are go to step 1766 and wait. If the doors are closed go to step 1708 and go through the checkout sequence. Back to step 1762, continue the checks at step 1772 to determine if the manual hold train doors open pushbutton is on. If the answer is yes, exit at step 1774. If not, check at step 1776 to see if the manual hold button is on. If it is on go to exit 1774. If it is off, go to step 1778 to check if the manual recycle doors pushbotton is on. Again, if it is on, the program goes to exit 1774. If it is off, close the doors at step 1780. Go to step 1708 to reset the hold train doors open flag in the status word. At step 1710 reset the hold train doors open output. At step 1712 start the headway timer. Step 1714 finds the train number from the TRNO table. Using the train number, go into the train length table at step 1716 to find the train length, and then send the train length to the next station at step 1718 to light graphic signals over the doors to tell the people in the next station how many cars are coming, and therefore how many doors will be opening. Step 1720 gets the run time to the next station, and it is stored in step 1722 for the next station. In step 1724 store the RBIT flag for the next station, which relates to the station bias number, and this bit is used to reset the alarm flags in the next station. Step 1726 sets the run flag for the next station to indicate a train is leaving this station, start timing to see if it arrives there on time. Step 1726 arms the alarm. Step 1728 sets the no-go flag alarm for the next station.

Step 1730 gest the train number from the TRNO table and step 1732 sends the train number to the next station. Step 1734 starts the train late clock in the next station. This clock is used to determine the train late alarms. Step 1736 saves the status word for use in the next program cycle.

The STRLOC table 1430 contains the train location table (TRLOC) 1415 addresses for the station track circuits. The station bias number is used to determine the table position of the TRLOC address. The station versus train location table address table 1430 of FIG. 23 is used to determine the train number of a train that is occupying the station track circuit.

The station status word (STATUS) table 1420 contains one word of flags for each of the stations. Each bit in these words is an individual flag denoting the status of some function involved in the station logic routines.

The station bias number is used to determine the location in the table of the word correlated with the particular station.

The MAXKT table is used to store the number of unit routes to be set up between the present station and the next station. This table contains one word for each station. The proper location is obtained by using the station bias number. The number of routes (MAXK) to be set up is stored in the table by the route select routine. When the route clears, the route setup routine zeros out the MAXKT table location for the proper station.

The ROUTT table contains the entrance number and exit number of each route which is required in order to reach the next station. Four words are provided for each station, which allows room for two routes, the maximum number of routes between stations.

The ROUTT table is used to store routes which are to be set up by the route setup routine. This table is a double word table, the first word contains the entrance number and the second word contains the exit number of each unit route which is to be set up. The proper station information is obtained by using the station bias number multiplied by four as a table bias. The unit routes to be set up are stored in the ROUTT table by the route select routine. When the route clears, the route setup routine zeros out the ROUTT table entries for the proper station.

The MINDW table contains the minimum dwell time for each of the individual stations. These dwell times will be used if the headway time has already elapsed. This table contains one word for each station. The proper location is obtained by using the station basis number.

The DWTIM table contains the dwell times in effect for the individual stations. Each station has one dwell time word in this table. The station dwell time table is used to store the dwell time in effect at each station. The proper location is obtained using the station bias number. Dwell times are entered into this table by the console input routines as a result of operator actions at the control console. Information in this table is used by the station exit routine to determine when to close the doors and release the train from the station.

The ETC Program shown in FIG. 27 consists of these routines:

a. Working Table Setup Routine 1800

b. Lockout Table Handler Routine 1802

c. Station Lockout Reset Routine 1804

d. Tripstop Lockout Handler Routine 1806

e. Turnback Lockout Cancel Routine 1808

f. Station Cancel Routine 1810

g. Run-Through Detect Subroutine 1830

h. Bypass Flag Handler Routine 1812

This program is the first of the train control programs to be executed in the program cycle. The functions involved as either special or provide information for several of the train routines. The first routine, Working Table Setup 1800, establishes the input working tables for the rest of the routines. It is important that the same information is being used by all programs during a given program cycle. The information the programs require is, in general, the present status of the input, whether a change of state has occurred, and which direction the change was made, from 0 to 1 or 1 to 0. To obtain this information, the program starts with the input word. The input is exclusive OR'd with the past value (the input word last cycle) to give the change of status bits. The word containing the changed bits is stored into the proper change table. The word of changed bits is logically AND'd with the input word to give the bits which have changed to the one state from the zero state. This word is stored in the Went to 1 table. The changes are then AND'd with the past value word to give the bits which have changed to zero state from the one state. This word is stored in the Went to 0 table. Finally, the input word is stored into the past value word for use in the next program cycle. This process is done for each word required for the following input functions:

a. Track Circuit Indications 1838

b. Gate Indications 1840

c. Switch Position Indications 1814

d. Gate Request Pushbuttons 1816

The second routine, Lockout Table Handler 1802, constructs the software interlocking lockout table. Routes are made not available by software lockout bits which act like track circuit occupancies. The track circuit input table (TK) 1842 is used to reset bits in the lockout table (LK) 1844. At this time, the track circuit indication itself is used to lockout routes. The LK table and the TK tables are "OR'd" together to form the software interlocking lockout table (TLK) 1818. The third routine, Station Lockout Reset 1804, clears the proper station lockout bits based on the clearing of certain gates. The station lockouts are used to keep two routes from being requested by two different stations or pseudo stations over the same piece of track at the same time. This routine cancels a station lockout when the gate clears for the other station indicating that no conflict now exists. The fourth routine, Trip Stop Lockout Handler 1806, sets the trip stop lockout bits based on the positions of the trip stops themselves and the turnback station at the east end of the system. If South D is not a turnback, routing is allowed over the trip stop into South Spur. The fifth routine, Turnback Lockout Cancel 1808, resets the proper software lockout bits beyond a given station when the trains turn back at their station. Normally the train would reset these bits as the route was taken, however, with the turnback set the train will never traverse the complete route, and the lockouts must be reset by other means. The sixth routine, Station Cancel 1810, resets the station status words, the station status words, the close door output bits, and train stored and train dispatch flags whenever the station track circuit becomes unoccupied. This cancel function is performed whether the train is being operated manually or automatically. It prepares the program for the next entry of a train into a station. This routine monitors the station bits in the track circuit went to zero (TKTOZ) table 1854. When one of the station blocks goes to zero, that station cancel function is performed. Different stations have different items cancelled. All stations have status words. No pseudo stations have doors. Six stations have train storage facilities. All functions present in a particular station are cancelled. The items to be cancelled are:

a. Station Status Words

b. Close Door Output bit

c. Stored Train Flag

d. Dispatch Train Flag

e. Run-through Alarm Flag

f. No Depart to Alarm Flag

The seventh routine, Run-through Detect Subroutine 1830, is used to reset the run-through alarm flag 1832 and the no depart to alarm flag 1836 whenever a station is bypassed. This will prevent the alarm messages from being generated falsely. If the run-through is in effect, the alarm flag bits are reset. The eighth routine, Bypass Flag Handler 1812, sets and resets the bypass flags. These flags are used in the routing program to set up the bypass shuttle operation. They cause one train to be held in either the bypass or station until the other train is in the proper position for a bypass operation to take place. This is required because of possible different run times over each half of the track.

Four Bypass Flags are used:

In FIG. 28, the ETC table setup routine is shown. At step 1900 the interrupts are disabled. The first column, starting at the second step 1902 is similar to the second column which is similar to the third column and with a little bit of rearranging, it is similar to the fourth column. This is the routine that sets up the went to one and went to zero tables that were previously discussed. At step 1902, set up the address pointers for storing this table information. At step 1904 set up the counter with the number of words minus one, because zero is a legitimate count. For the track circuit inputs, which is the left hand column, there are four words, so set the counter equal to three, the other three tables have two words. At step 1906, get the input word and at step 1908 exclusive OR it with the past value and at step 1910 store in the change table. Take the changes, AND them at step 1912 with the inputs, and store at step 1914 in the went to one table. Get the changes again, at step 1916 AND with the past values, and at step 1918 store in the went to zero table. At step 1920 the present input is stored in the past value table for the next cycle. At step 1922 check the count to see if the routine is finished. If yes, go to the next section of the routine, and if not, increment and through the routine again. The gate pushbutton tables routine includes additional steps. Steps 1924 and 1926 are used for the pushbutton cancel function and to develop the PB cancel table. Steps 1928, 1930 and 1932 take the went to one words, then AND's with the gate pushbutton inputs to develop the PBSET table.

The LKOUT routine shown in FIG. 29 constructs the software interlocking lockout table (TLK). The TLK table is derived from the track circuit input table (TK) and the software lockout table (LK). The lockout table handling routine is used to construct the software interlocking table (TLK) as track circuits become occupied or unoccupied and as routes are cleared and cancelled. The track circuit input table (TK) is used to reset the software lockout table (LK). This is possible because a track circuit occupancy makes a route unavailable. The TK table is AND'd with LK table. Then the TK table is OR'd with the LK table and the result is stored in the TLK table. This lock outs any track circuit which is occupied or has a software lockout bit set.

FIG. 29 shows the lockout table handling routine that was previously discussed. At step 2000 set the counter, get the track circuit inputs at step 2002, at step 2004 compliment them, AND with the software lockouts at step 2006 to cancel out of the table every track circuit input that is present. At step 2008 store them back into the software table, and at step 2010, OR that value with the track circuit input. At step 1012 store the track circuit lockouts in the TLK table.

The STALK routine shown in FIG. 30 resets the station lockout bits which were set in the station logic program. These lockout bits are used to prevent two stations from requesting a route over the same area at the same time. The station lockout bits are reset based on the clearing of gates. This routine resets the station lockout bits when gates clear or when gate pushbutton requests have been made by the console operator. The gate indication words are OR'd with the gate pushbutton input words. The result is AND'd with the station lockout words.

FIG. 30 shows the station lockout reset routine to the station lockout bits. At step 2020 get the gate input, and exclusive OR it with the gate pushbutton input at step 2022. At step 2024 complement the result, then AND that with the lockout at step 2026 and store in the table at step 2028. This is done for both words of lockout such that if either the pushbutton or the gate indication clears, this zeros the bit out of the lockout order.

The TSPLK routine shown in FIG. 31 sets the resets the trip stop lockout bits as required by the status of the system. If the stops are in the raised position, routes are not allowed across them.

The lockouts are used by the route available routine to prohibit running a train over a trip stop in the up position. The trip stop input word is complemented and stored in the lockout word.

The LKCAN routine shown in FIG. 33 cancels the lockout bits in the LK table that the train does not cancel when it turns back in the middle of a route. All lockout bits from the station involved to the end of the route are reset.

In FIG. 33 there is shown the lockout cancel in turnback routine, which operates when a train turns around at a station in the middle of a route, and it becomes necessary to cancel the lockouts beyond that station. At step 2040 get the turnback output buts, which are generated by the computer or console pushbuttons, depending on the mode. At step 2042, the turnback input, which is generated from a pushbutton on the operator's console, is OR'd together with the turnback output, and at step 2044 stored into the TRNBAK table. At step 2046 get the run-through inputs, complement them at step 2046, at step 2050 and with the TRNBAK table to cancel the bits out of the table and store the result in TRNBAK table At step 2052. This TRNBAK table is now used throughout the program when a turnback is used. In horizontal line 2054 are set forth the names of the particular stations in the track system shown in FIG. 3 that can have a train turnback in the middle of a route North A is the first one, North C, North D, and so forth. The first check is if the station is occupied, and if not, there is nothing to do, and the program goes to next station and continues the test. Each station will be checked once during each cycle, and if it is occupied, in line 2056 a check is made to see if the station turnback pushbutton is on. If the pushbutton is not on, there is nothing more to do, so go to the next station. In line 2058 are predetermined lockout bits that are reset in relation to each station in line 2054 which was occupied and had its turnback PB on.

The STACAN routine shown in FIG. 34 performs the functions required to reset the station logic whenever a train departs from a station.

The different stations have different things to cancel when becoming unoccupied. The first station checked, in column 2068 is North Baggage to see if the station just became unoccupied. This is determined by using the TK went to zero table. When it becomes unoccupied, North Baggage requires a reset of the status word, close doors output, the store flag and the dispatch flag. The next station in column 2070 is South Baggage, and it has the same things to reset. The next station is North Ticketing in column 2072, the only things that are required to be reset are the status word and the closed doors. Each succeeding column is for a different station and under it are the things that have to be reset.

The ALR subroutine shown in FIG. 32 detects whether a station run-through has occurred. If it has, the run-through alarm bit is set provided that the run-through alarm flag had been previously set. The run-through alarm flag for the next station is set and the run-through alarm flag for the present station is reset. The no depart to flag for the next station is set.

The BYFLAG routine shown in FIG. 35 sets and resets the four bypass flags, NBY, SBY, NST, SST, as required depending on mode of operation, as track circuits becoming occupied and unoccupied.

These flags are used in the automatic routine program to inhibit routes unless the trains are in proper position to perform a bypass operation. NBY and SBY inhibit routes into the bypass tracks. NST and SST inhibit routes into the straight through tracks. Whenever one of the four bypass flag track circuits becomes occupied, the respective flag is reset.

a. 14T resets NST

b. 15T resets NBY

c. 37T resets SST

d. 38T resets SBY

The flags are set only if the particular track is operating in bypass mode. The flags are set as follows:

a. North track in bypass, 14T unocc, set NST

b. North track in bypass, 15T unocc, set NBY

c. South track in bypass, 37T unocc, set SST

d. South track in bypass, 38T unocc, set SBY

FIG. 36 shows the fetch subroutine, which determines the status of a bit specified in WORD. This word has a right-hand digit that contains the bit position and the left-hand three digits contain the location in the memory. At step 2100 save the X register, and at step 2102 put WORD in the X register. At step 2104 mask out the bit number to save the four low bits and in step 2106 exchange with the X register, to take WORD out of the X register and put WORD back in the A register and put the bit position into the X register. At step 2108 isolate the memory address by masking out the digit that has the bit position. At step 2110 go get the specified word out of memory. Step 2112 masks out the desired bit and leaves it in the A register. At step 2114 restore the X register and then return to the calling program. If the bit was not present, the A register will contain zero, and if the bit was present, that particular bit is in the A register.

FIGS. 37, 38, 39, 40 show similar pack routines. FIG. 37 is PACK 1 routine which sets the bit specified in WORD to a one. FIG. 38 is called pack zero, which sets the bit specified in WORD to a zero. FIG. 39 is called pack Z50, and resets the bit specified in WORD to a zero. The difference in these is the FIG. 39 pack zero routine zeros a bit out in page 50 which is addressed as 5000, and the FIG. 38 pack .phi. operates to zero a bit out in page 51 which is the 5100 address. For each of FIGS. 37, 38 and 38, in step 2130 save the X register. In step 2132 put WORD in the X register. In step 2134 mask out the bit position number and in step 2136 store the bit position in the X register. In step 2138 get the contents of the memory address, and at step 2140 in FIG. 37 and FIG. 38 add the bias of 5100, at FIG. 39 add a bias of 5000, to obtain the right page of memory for this operation. Step 2142 gets the word out of memory. Step 2144 is a little different, in FIG. 37, it sets the bit and in FIG. 38 and FIG. 39 it resets the bit. Step 2146 stores the word back in the memory, and step 2148 restores the registers and then returns.

FIG. 40 is the PACK .phi..phi. routine, which is used to cancel switch positions. Each switch position has a request normal bit and a request reverse bit, and the program cancels them both. In step 2160 save the X register. In step 2162 mask out the bit. In step 2164 store it in the register. In step 2166 get the normal switch request word. In step 2168 zero out the bit. In step 2170 store the normal switch request. In step 2172 get the switch reverse word and in step 2174 zero it out. In step 2176 store it away, and in step 2178 restore the X register and exit.

FIG. 41 shows the ETC program tables that were discussed in relation to the ETC program of FIG. 27. Table A includes the gate working tables, which are five two-word tables, the first is the gate inputs, the second is the gate past values, the third is the gate changes, fourth is the went to one; and fifth is the one went to zero. Table B includes the similar five tables for switch inputs. Table C includes the similar tables for the track circuits. Table D is the similar tables for the gate pushbuttons, and has two additional tables. They are the PB set and the PB can. For the PB set, the went to one and the previous value is OR'd into the word. For the PB cancel the went to zero and the previous value are OR'd into the word. Table E is the lockout tables, including the pushbutton switch lockouts, the software lockout, the software lockouts OR'd with the track circuit inputs, and the station lockouts. Table F is the status word address table, each one of the stations has a status word, and this table tells the program where those 16 words are stored. Table G is the bit table, a 16-word table, each word containing one bit. The bit table is used in the fetch and pack routines to set or detect a bit. Table H is the complement of the bit table, so it is the not-bit table, having 16 words and it contains all bits but one. The not-bit table is used by the pack .phi. routines to reset bits.

The established route table (ESTRT) shown in FIG. 10 contains five words of information about every established unit route under three labels, ESTRT, ESTKEY and ESTTK. This information is used to cancel a route that has been set up. This table is used to store unit route information for all established routes. The table contains five words of information about every route under three labels.

This table is constructed by the route setup routine and zeroed by the cancel routines. As soon as a route being set up clears, the information is stored in the table. The program stores a unit route's information in the first open slot in the ESTRT table. Therefore, no particular order is possible for a through route. The ESTRT table contains a group of independent unit routes, each route that is set up. Routes are cancelled from the ESTRT table automatically when a train takes the route or from a manual PB cancel request from the control console.

The tracking control system disclosed in the above-referenced patent application concerns the direction signals, and the way information tables are set up to keep track of them and which way they are going. These direction signals come from any one of hardware interlocking, gates clearing or a station turnback. The present routing control system determines the operation of trains from any one station to any other station on the track system that actually has a path between them depending on the operator pushbuttons that are set on the console, the mode of operation that the train is running in, and any extra commands that are put in such as store and dispatch. Routing is getting a train to any station from any station depending upon conditions by sorting out information that is available from interlocking. For each station there is established in a table a list of available routes, by identifying every possible route and putting them in a permanent table. When a train comes to that station and is going in a known certain direction, a check is made as to what route is available. A selection is made of the most desirable from among predetermined available routes. Every route has predetermined operation conditions that must be satisfied, such as the track circuits occupied, the train going the wrong direction to oppose a signal cleared against it or the train running an uncleared signal and so forth in accordance with the general interlocking rules that are well known.

For the illustration shown in FIG. 42, assume the train wants to go from point A to point B. There are two paths and only two, and these routes are set up based on actual signals shown at 101, 103, 105, 107, 111 and 113. The signals 101, 107 and 109 are pointing in the direction from station A to station B. The first thing is to assign all of the signal gates the identification numbers, as shown in FIG. 42. Then, using the entrance 101 a search is made in the entrance/exit tables until the entrance 101 is found. Then somewhere in the AR(I) tables there is a route 101 to 109, with several conditions. If every one of those conditions is satisfied, the route is available. Then check for the next point 109 for the route in the direction from 109 to 113, which is part of the route from 101 to 113. The route of interest is from 101 to 109. When route 101 to 109 is found to be available, then take the exit which is 109 and make it the entrance for the next route, so find 109 to 113 and see if it is available, this gives two routes in the table, namely, routes 101 to 109 and 109 to 113. Now check to see if there are any other routes that have 101 as an entrance. The answer is yes, since route 101 to 107 is in the entrance/exit table. A check is made to see if 101 to 107 is available, and if so, then take 107 and make that the new entrance and check if 107 to 113 is available. If the answer is yes, in the available route table, ENTAV, there are four routes. Now go through ENTAV and see if there are two exits in that table that are the same, and if the answer is yes, that means there is more than one path. There is no way to have two numbers the same unless the train can get there from two paths. Go to the priority routine and select which one is the first choice. In all cases the straight through route is the preferred route.

A check is first made that a route is available and then the priority check is made to determine the best route, then the route is set up, by requesting the route from interlocking. If it is safe to throw the necessary switches and give clear the required gate, interlocking actually sets up the route.

In FIG. 43 there is shown the track arrangement including the North ticketing station NT, the North baggage station NG, and the South ticketing station ST, and assume the trains are running in normal mode. Train B is in North baggage when a second train A arrives at North ticketing. A third train C is stored in South baggage SG, which is not on the route until the operator wants to dispatch it.

An arbitrary sequence can be set up here to control the movement of the trains. For example, train B will go out of station NG first and then train A will go into station NG from station NT and last will be train C that is dispatched from station SG. This sequence is arbitrary, any order can be selected. When the train in one of these three stations NT, NG and ST requests a route, a station lockout operates to lock out the other two stations so their trains cannot make any request. In response to a train requesting a route, the software lockouts are set up after the check is made to see if a route is available. When one of these trains requests a route, a lockout is provided in relation to the other two trains, and then as the gate clears these lockouts are eliminated.

When a train pulls into a station, and the doors start to open, the train requests a route to the next station. The first thing is to determine what the next station is, and then go through the available tables to determine if a desired route is available. If the answer is yes, the train then locks out all other trains in the area without looking to see if there are any other trains there. This lockout is in relation to anyplace where two or more stations can request a route over the same area. Once a train sets the route up then the track circuit software lockouts are set and no other train can travel that same route until the first train enters and leaves the station and then the lockouts are clear.

There are two tables provided for established routes. As soon as the route is set up all the lockouts are set, and then the route information is stored in the ESTRT table which is the established table. This table includes the route entrance, the exit, the keyword, the keyword plus one and the exit track circuit. Assume, as shown in FIG. 43, a route is desired from station NG to station ST. The station NG is in track circuit 2T. The station NT is in track circuit 5BT. On the south track the first station is SG in track circuit 27T, the switch 2 is in 28T, the switch 4 is in track circuit 29T and the station ST is in track circuit 30BT.

When gate B clears, software lockouts are set for track circuits 3T, 28T, 29T, 30AT and 30BT. In the ESTRT table, the entrance is 100, the exit is 204, the keyword location is some number, the number of words of information is some number, and the exit track circuit for the route is 30BT. The train starts to move. The first thing that happens when the train leaves the station NG is that the track circuit number 3T becomes occupied. Switch 1 is in track circuit 3. The gate B is in track circuit 3T. There is a lockout set for track circuit 3, so the program goes into the lockout table and cancels out the 3T lockout. The switch 1 request is canceled because it is in track circuit 3T and the gate B request is canceled because it is in 3T. The train moves down into track circuit number 28T and cancels the 28T lockout and cancels the switch 2 request because number 2 switch is in 28T. The train moves into track circuit 29T and cancels the 29T lockout and cancels the switch 4 request in track circuit 29T. The train then moves into the next track circuit 30AT, and cancels the 30AT lockout.

The train moves into the 30BT, and cancels the lockout in 30BT. In the ESTRT table, every program cycle a check is made of the exit track circuit occupancy, and as soon as 30BT exit track circuit becomes occupied, the program cancels all five of those locations in the established route table and all traces of the train in the track circuits 2T, 3T, 28T, 29T, 30AT and 30BT are gone. So based on a track circuit by track circuit movement the route is sectionally released, but the route from station NG to station ST which would permit a different train to travel this route does not clear until the last track circuit in that particular route is occupied.

In the station programs doors open in the point in time when the routes are requested and checked. All the available routes are set aside in their individual ROUT tables, which are the individual route tables. After all the station programs are finished, all 16 stations have been processed, control is transferred to the setup program. The setup control program looks at the first station and determines if there are any routes to be set up. If the answer is yes, the routes are set up, and if the answer is no or after the route is done, the program goes to each station in sequence. The next program operation is the cancel routine which cancels a route as the train goes through the route.

FIG. 44 shows the MODE word, which is one word in memory and the specific bits show what mode the system is operating in. These bits are determined by the operator's console, where the operator selects pushbuttons and thumb wheel switches. Each bit represents one particular route. Two special bits, bits E and F, are set up to specify no mode for a particular track. Bit F indicates there is no mode on the north track and bit E indicates no mode on the south track.

FIG. 45 shows the station STATUS word. There is one word for each station. The bits in the word are set as predetermined events occur. The information is used to sequence a train through the station. The word is reset when the station becomes unoccupied.

In Apendix A there is included an instruction program listing that has been prepared to control a process operation, such as a transit passenger vehicle in accordance with the here-disclosed control system and method. The instruction program listing is written in the assembly language of the Computer Automation LS12-20 computer system. Many of these computer systems have already been supplied to customers, including customer instruction books and descriptive documentation to explain to persons skilled in this art the operation of the hardware logic and the executive software of this digital computer system. This instruction program listing is included to provide an illustration of one suitable embodiment of the present control system and method that has actually been prepared. This instruction program listing at the present time is a more or less development program and has not been extensively debugged through the course of practical operation of vehicles on a transit system. It is well known by persons skilled in this art that real time process control application programs may contain some bugs or minor errors, and it is within the skill of such persons and takes varying periods of actual operation time to identify and correct the more critical of these bugs.

A person skilled in the art of writing computer instruction program listings, particularly for an invention such as the present transit vehicle control system must generally go through the following determinative steps:

Step One-Study the transit vehicle operation to be controlled, and then establish the desired control system and method concepts.

Step Two-Develop an understanding of the control system logic analysis, regarding both hardware and software.

Step Three-Prepare the system flow charts and/or the more detailed programmer's flow charts.

Step Four-Prepare the actual computer instruction program listings from the programmer's flow charts.

The instruction program listings included in the Appendix were prepared in relation to the programmer's flow charts.

The manual routing program listing is operative in accordance with the program routines and subroutines illustrated in FIG. 10.

The automatic routing program listing is operative in accordance with the program routines and subroutines illustrated in FIG. 16.

The station logic programs listing is operative in accordance with the program routines and subroutines illustrated in FIG. 23.

The ETC program listing is operative in accordance with the program routine illustrated in FIG. 27.

In relation to the typical routing control system sequential operations shown in FIG. 9, the ETC program would be the operation shown in block 208. The station logic programs illustrate an improvement of the blocks 216, 218, 220, 222 and 224. The other blocks 200, 202, 204, 206, 210, 226 and 228 are believed to be within the routine skill of this art to implement in accordance with the system description here provided. An improvement of blocks 212 and 214 is illustrated in the above cross-referenced related patent application. ##SPC1## ##SPC2## ##SPC3## ##SPC4## ##SPC5## ##SPC6## ##SPC7## ##SPC8## ##SPC9## ##SPC10##