GB1352416A - Track communications for continuous rail - Google Patents

Abstract

1352416 Track circuit system GENERAL SIGNAL CORP 4 May 1971 [4 May 1970] 13097/71 Heading B7N In a continuous rail, alternating current, track circuit system in which each occupancy detecting track circuit is terminated by shunts S and includes a centre feed transmitter T1 or T2 co-operating with receivers R1 or R2 at the circuit ends and in which the track circuit frequency alternates in successive circuits, a further set of control track circuits including transmitters TA or TB, operating at frequencies different from each other and transmitters T1 and T2, and receivers RA or RB is provided overlapping the first set of circuits and coupled to the first set to transmit occupancy information to track locations along the line. Assume a train between positions 3 and 4, this is detected by the absence of signal from transmitter T2 to receiver R2 at position 3. This information is passed to transmitter TB and passed via the tracks to receiver RB at location 2 and via transmitter T1 and the track to receiver R1 at position 1. Similarly the train is detected by receiver R2 at position 5 and this information is passed in the direction of locations 6 and 7. Each transmitter signal can be coded, e.g. with its numbered location and with message words indicating track occupancy or the state of an associated visual signal. In addition each location can include a further transmitter which is switched on by train movement and transmits cab signals or speed information to the train from a central office.