GB909374A - Railway traffic control systems - Google Patents

Abstract

909,374. Central traffic control systems. GENERAL RAILWAY SIGNAL CO. May 4, 1960 [June 3, 1959], No. 15732/60. Class 105. In a traffic control system, two indicating means are associated with each track intersection on a track diagram, the first indicating means showing the actual setting of track switches and signals at the intersection and the second indicating coincidence or non-coincidence between certain of the actual settings and the desired settings as indicated by the position of the track switch and signal setting levers. Assuming the track switch and signal of field station No. 1 on the track layout (not shown) are to be set to normal and clear left respectively, track diagram levers WL, Fig. 1A, and GL, associated with station No. 1 on the track diagram are moved to N and W respectively and the command is transmitted to the field station by code communication apparatus. In this apparatus the return indication code from the field station comprises first an identification code signal which is applied via step relay contacts to registration relays R1-R4 and RX, in the example chosen, the code is such that relays R1-R3 remain de-energized and relays R4 and RX are picked up, whereby station No. 1 relay 1ST is energized via an obvious circuit which includes lead 70. This is followed by an indication code signal which is applied to indication relays NK (track switch normal), RK (track switch reverse), RGK (signal clear right) and LGK (signal clear left) and these relays are picked up, or remain released, in accordance with the actual state of the track elements at the field station, in addition relay WKP is energized when either relay NK or RK is picked up. At the end of the code tranmission relay LV is picked up and common buses 1-5 are energized in accordance with the state of the indicating relays, in this example, as shown in Fig. 4, a positive potential is applied to buses 2, 3 and 5. Buses 1-5 are connected via diodes 1D-5D and buses a-e to display unit 1KU in which a motor M is driven by the coded signal via front contact 12, relay 1ST until the display unit assumes the required indication as shown in Fig. 4 and motor-driven switch contacts 2B, 3B and 5B associated with energized buses 2, 3 and 5 are open and contacts 1B and 4B associated with de-energized buses 1 and 4 are closed. When the communication system enters a period of rest the code registration relays and relay LU release releasing relay IST, whereby lamp LGE is energized via back contact 10 relay IST, switch contact 26, motordriven contact 4B and back contact 11 relay IST, indicating coincidence between the actual and required signal setting. Similarly, lamp RGE is energized when the actual and required settings are clear right. When the desired signal is at stop lamp WE is energized when the desired and indicated setting of the points are not coincident.