Patent GB-972760-A (GB)
Title: Automatic signalling and train control system
IPC: B61L27/00
Filed: 1961-01-18
Abstract: 972,760. Automatic train control systems. J. R. SHEPARD. Jan. 18, 1961 [Jan. 18, 1960], No. 2095/61. Heading B7N. An automatic train control system comprises means on each train in a track network for transmitting to a central office information relating to the train's identity, the identity of the last trackside marker passed by the train, the distance travelled by the train, the aspect of the signal currently displayed in the train cab and the control currently being applied to the train and at the central office means for storing the information received from each train in the network being controlled, computer means for analysing the information received and for issuing control instructions to the trains, via transmitting means at the office, in accordance with the differences between the actual position of the trains in the network and the desired positions. The trackside markers, 42, 43, Fig. 7, generate signals when energized via a switch operated by the flange of the leading wheel of the train which are picked up by receiver 64, Fig. 4, on the train. The signal indicating that the train has passed the marker is temporarily stored in register 47 and then transferred to register 31. Each revolution of the front axle of the train generates a signal 12 which triggers a multivibrator 28 via detector 27. The multivibrator signal operates a stepping switch 29 which is coupled to an encoder 30 in which the angular position of the switch is converted to a binary number indicative of the distance travelled by the train. When a gate 40 is open a second output from the multivibrator transfers the number to a register 31. Similar circuitry 12<SP>1</SP>, 27<SP>1</SP>-31<SP>1</SP> measures the distance travelled by the rear axle of the train. The signal from the central office comprises a first train identity signal followed by the control instructions. This signal is received by the communication receiver 35 and applied via frequency shift receiver 25 to a two-way gate 36. The gate output is normally connected to comparer 37 in which the transmitted identity signal and the train identity signal from set switch 33 are compared. Agreement of these two signals operates a control unit 38 which switches the gate 36 to its second output position in which the control signals for the train are fed to an instruction register 32 and thence to a cab display unit 21 and train operation control bank 22. The instruction register also issues a readout signal which brings a report sequencer 39 into operation. This resets the two-way gate 36, energizes the transmitter 34 and closes gates 40 and 40<SP>1</SP>. It then issues a series of pulse trains which interrogate in turn the identity set switch 33, the register 31 which stores the identity of the last track marker passed and the distance as measured by the leading axle of the train, the register 31<SP>1</SP> and the signal aspect and instruction register 32, to pass the information stored to the transmitter for transmission to the control office. At the central office the receiving section of the control office transceiver applies the signal via gate 58 and gate 59 to location register 60 which stores the train identity, the identity of the last marker passed and the distances measured by the leading and rear axle of the train. When the number of digits corresponding to this information has been counted by counter 61, the counter switches gate 58 to its second output position to feed the aspect and control information to register 62. This supplies a signal to control sequencer 63 to start the transmission of instructions to the train. These instructions are obtained from a computer (not shown) to which the trains location and identity information is supplied and are stored in register 69 and after transmission in register 64. The first signal from the sequencer interrogates registers 62 and 64 whereby the returned control information for the train and that intended for control are compared in circuit 65. If an error exists a counter 66 is operated and a gate 67 is closed. The second signal from the sequencer resets counter 66 if the gate 67 is not closed. The third signal from the sequencer operates the transmitting section of trans-receiver 51 via gate 68 and interrogates register 69 whereby the train identity and control signals are transmitted to the train. The fourth signal from the sequencer resets gate 67. If an error is detected on three successive cycles, as counted by counter 66, an error signal is passed to the computer.