Patent GB-248320-A (GB)
Title: Improvements relating to railway traffic controlling apparatus
IPC: B61L3/12
Filed: 1925-09-11
Abstract: 248,320. Westinghouse Brake & Saxby Signal Co., Ltd., (Assignees of Loomis, H. S.). Feb. 25, 1925, [Convention date]. Electrical systems, automatic; track apparatus for stopping trains.-In a railway traffic controlling system employing control devices located in the track co-operating with train-carried speed-governing devices, the circuit for electrically controlling the track device is included in the circuit of a relay by which the device is controlled. The arrangement described ensures that an indication shall be given by any defect in the circuit of the control device, and comprises a track indicator K, Fig. 1, having a winding 5 opened or closed by a short-circuiting contact 6, and a train-carried inductor M having legs provided with windings 8, 9. Winding 9 is initially energized in series with a relay 11 from a battery 10 by momentary closure of a hand-operated contact 19, the circuit being thereafter energized through a stick circuit including contact 16 of the relay. A contact 49 of relay 11 closes the circuit of winding 8 which is energized from a battery 21 in series with a relay 22 serving to apply the, brakes when deenergized. The fluxes due to coils 8, 9 are in opposition, and the arrangement is such that when the air-gap of device M is bridged by passage over the device K, no change is effeated if contact 6 be closed, but if contact 6 be open, the change of flux produces an induced current in opposition to battery 10 sufficient to de-energize relay 11 and consequently relay 22. applying the brakes. Release is effected by again closing contact 19. The track rails 1, 1<a>, Fig. 2, are divided into insulated sections at A, B, C and each section has a track relay Q<A>, Q<B>, Q<C> at the entrance end energized by a track battery 3 at the exit end. Each track relay is associated with a line relay H<A>, H<B>, H<C> controlled by the track relay of the section ahead, a signal S<A>, S<B>, S<C> shown as comprising three lamps R, Y, G, and a track inductor K<A>, K<B>, K<C> the winding 5 of which is controlled by contact 6 of the line relay ahead. Each winding 5 is included in the circuits of the signal lamps and line relay ahead, so that any break &c. in the winding prevents the signal lamps from lighting and causes a brake application. The circuits of all sections are similar. Line relay H<B> is energized from a battery P<C> over front contact 24 of relay Q<C>, conductor 25, front contact 26 of relay Q<B>, winding 5 of inductor K<B>, conductors 34, 29, relay H<B>, and conductors 30, 32. Energization of a line relay thus depends on simultaneous energization of the adjacent and next ahead track relays. A vehicle W is shown de-energizing relay Q<C> and consequently relays H<B>, H<C>. The short-circuit of winding 5 of magnet K<C> is broken at contact 6 of (relay H<C>, causing brake-application on a train passing K<C>. A signal circuit is closed through danger lamp R of signal Sc from battery Pc over back contact 24, and winding 5 of inductor K<C>. Relay Q<B> being energized and relay H<B> de-energized, a circuit is closed through caution lamp Y of signal S<B> from battery PB over front contact 42 of relay Q<B>, back contact 44 of relay H<B>, lamp Y, conductor 40, and winding 5 of inductor K<B>. As the shortcircuit of the winding of inductor K<B> is open at contact 6 of relay H<B>, a brake application occurs on a train about to enter the " caution " section. Relays Q<A>, H<A> being both energized, a clear signal circuit is closed through the lamp G of signal S<A> from battery P<A> over front contact 44 of relay H<A>, and contact 6 of relav H<A> short-circuits the winding of inductor K<A> so that no brake-application occurs on a train entering the clear section. A diagram is given showing the application of the invention to a three-position semaphore signal.