Patent GB-975515-A (GB)
Title: Apparatus for controlling the change of speed of a vehicle along a route
IPC: B61L3/22
Filed: 1961-04-25
Abstract: 975,515. Automatic train control. WESTINGHOUSE AIR BRAKE CO. April 25, 1961 [April 25, 1960], No. 14861/61. Heading B7N. An automatic train control system, particularly for unmanned trains operating between stations A and B on a track 2, 3 divided into insulated sections X, Y and Z, comprises means for continuously supplying section Y with coded track current, means for selectively supplying sections X or Z with similar current, pick-up means on the train operative to prevent a brake application during receipt of the coded current and to bring into operation, during non- receipt of the current, means whereby the retardation of the train is controlled so that it comes to a halt within a predetermined zone. Assume the trains has to move from station A to station B, sections X and Y are supplied with coded current and the train proceeds normally until it reaches the junction of sections Y and Z. During this period energy picked up by rails 10 energizes relay 12, whereby two time delay relays 22, 23, which release after preselected time periods of 20 and 30 seconds respectively, are energized and electromagnetic (E.M.) valves 92, 93 which are operated respectively by potentials on application wire 75 and release wire 20, are released and energized respectively, disconnecting pressure fluid supply pipe 95 from straight air pipe 96, which supplies the brake pressure, and venting the straight air pipe to the atmosphere. On cut-off of the coded current relay 12 releases, opening the energizing circuit of relays 22, 23 and the circuit of E.M. valve 93 and closing the energizing circuit of E.M. valve 92. Thus the brakes are applied with increasing pressure by pressure fluid supplied from pipe 95 to the straight air pipe 96 and the brake cylinder 89. Contact MR of a retardation measuring device 27 is also energized and when the retardation reaches a medium value contacts MR and 80 engage and energize a quick release relay 24. The circuit to E.M. supply valve 92 is broken at back contact (b.c.) 74 of this relay and via its front contact (f.c.) 72 a potential is applied to release wire 20 which operates E.M. valve 93 and vents the straight air pipe until the retardation drops to a value at which contacts MR and 80 disengage and the circuit to valve 93 opens. The brakes remain at a pressure which provides this medium retardation until the delay of 20 sees. expires and relay 22 releases. The action of the equipment on release of relay 22 depends on the condition of relays 51, 54 which are controlled by a speed control switch 25. This switch is operated by a speed governor and assumes a position in which contacts 45 and 46 are bridged, and relay 51 energized, at speeds above 11 m.p.h., contacts 47 and 48 are bridged, and relay 54 energized, at speeds below 9 m.p.h. and neither set of contacts bridged, and both relays released, at an ideal speed of 10 m.p.h. The position of f.c.s. 62, 64 and b.c.s. 63, 65 of relays 51 and 54 determine which of the retardation measuring device contacts, HR (speed above 11 m.p.h.), MR (speed at 10 m.p.h.) or LR (speed below 9 m.p.h.) are energized. On release of relay 22 the hold circuit of relay 24 is broken and E.M. supply valve 92 is re-energized. When contact 80 swings to a position in which it engages the energized retardation contact, relay 24 is again energized, closing the E.M. supply valve 92 and venting the straight air pipe via valve 93 until the contacts disengage. The train then proceeds with the new (or uncharged) valve of retardation until relay 23 releases and initiates a similar action controlled in this case by speed control switch 26 which assumes a mid-position at an ideal speed of 5 m.p.h. The final setting of retardation brings the train to a halt at station B.