Patent GB-1321053-A (GB)
Title: Control of vehicle systems
IPC: B61L27/00
Filed: 1970-09-24
Abstract: 1321053 Train control WESTINGHOUSE ELECTRIC CORP 1 July 1970 [9 July 1969] 31826/70 Heading B7N In a railway system in which the speed of trains is controlled basically in response to the occupancy of the track in advance, the speeds are also controlled from a central computer responsive to the overall traffic position. The basic control is exercized via the track arrangement shown in Fig. 2 in which the continuous track is divided by shorting bonds 30 into track circuits fed at their exit ends from block signal transmitters 31 and having block circuit receivers 35 connected to the bonds at the entry end. The receivers control speed level encoders 37 which determine the speed signals applied to the circuits for pick up on the train via coils 36, Fig. 3B. On the train the speed signal is applied via receiver 38 and a speed code modification circuit to a train movement controller 40. At each station stop, unless disabled by a signal from the control computer, a station stop transmitter 48, Fig. 3A, feeds a crossed over line 46 coupled by coil 47 to a programmed stop receiver 49 on the train. The pulsed signal is fed to a stop computer 50 which provides a control signal to the movement controller 40 to bring the train to a halt. At each station a further communication link with a train is established by loop 42 which co-operates with pick up loop 43 on the train to couple bidirectional frequency multiplex terminals 44, 45 on the track and train respectively. Where the station is a terminal or turnback point a train identification and destination transmitter 52 on the track supplies a signal via the multiplex terminals to a receiver 53 on the train which stores the information in a memory 54. As the train approaches the station an advance loop 42a receives a signal which operates a " doors open " transmitter 58 on the track. This supplies a signal via the multiplex terminals to a doors open receiver 59 on the train which operates the doors controller 60 when detector 61 indicates that the train has come to a halt. At this, continuously operating transmitter 55 which is coupled to the multiplex link and normally modulated with the train identification and destination signal from memory 54 has the modulation removed and this removal is detected by the door status, destination and identification receiver 57. This removal is taken as an indication of train arrival and is passed via the local terminal 51 of a telemetry system to the central computer. It also operates a local time controller 62 which in the absence of a hold signal from the computer due to some fault, can generate a signal to cancel the doors open command-this being the departure signal to the train. Normally this action is produced by a release signal from the computer on line 51d. After the train has received its departure signal the central computer supplies via speed PL command transmitter 64, multiplex link 44, 45, speed PL receiver and memory 65, 66 a performance level (PL) signal to the speed modification circuit 39 to modify if necessary the speed signal supplied from the basic control system. Where the central computer determines that to assist time keeping a train should run through a station this is effected by a signal on line 51f which disables the stop transmitter 48 and the " doors open " transmitter 58. Stations are thus performance adjustment points in the system from which arrival and departure information is supplied to the computer and speed performance, hold and release commands, station run through commands and train identification and destination assignment are given to the train. Track side loops are also provided at interlock points where the tracks converge or diverge. In the arrangement shown in Fig. 4, the destination and identification transmitter 55 on the train is coupled via loop 42b to the destination code receiver 71 which supplies a signal to the switch actuator 72 to correctly route the train and also to the local telemetry terminal 73 which communicates the identity to the central computer. The track circuit at the junction includes transmit loop 68 which couples with each of the three branches and three receivers 33s which signal the train presence to the central computer via terminal 73. At converging junctions the block signal system controls approach on a first come first served basis. The input signals from the control pointstrain identity, location, depart and arrive times and the output signals to these points-hold, release, speeds PL, connect to the input and output interfaces 110, 112 at the control computer which includes " run train to schedule " routine 120 and "modify train schedules"  routine 122. Initial input data 124 is supplied comprising the original schedule 128, normal run times between section 136 and normal dwell times at station 140. The routine 120 includes a modified schedule 132 which starts as the original theoretical schedule but is changed in response to delays &c. to provide a best estimate of arrival times. Where a train is slowed down, but not because of its own fault, the theoretical schedule is changed along with the modified schedule to prevent the train getting a bad performance index. Subroutine 148 receives the real time data from the control points, the initial input data and that from the schedules and predicts the behaviour of the trains which is then fed into the modified schedule 132. Calculated dwell times at stations and performance levels are fed to the output interface 112 at which they are converted to hold, release and PL commands for the trains. The subroutine 148 is connected to the " modify train schedule " routine 122 in which in unit 172 the performance index of each train (its degree of lateness) is determined and stored in table 178. At intervals of time the performance index of the whole system is assessed in unit 186 and if necessary the whole system can be offset by time shifts which are communicated to the modified and theoretical schedules. At other times the performance of each train is assessed in branching table 194 to produce strategies which can correct for or minimize the effect of a trains low performance index such as redistribution in time of the trains in advance of and behind the train by operating on their dwell times at stations &c., or drastically to allow it to run through a station without stopping.