Patent GB-191402571-A (GB)
IPC: B61L3/02
Abstract: 2571. Angus, A. R. July 28. Electrical systems, non-automatic; track apparatus actuating signals on trains, and for stopping trains.-The circuit from a track generator to a track relay, arranged to be short-circuited by a train on the section, is closed by a relay in a normally-open circuit closed by a train contacting with a track contact, the track relay controlling the circuit through the track contact to the apparatus on the train. The apparatus serves to actuate signals or train-stopping apparatus in any of the following circumstances in spite of failure or error on the part of an operator : -(a) a broken or displaced rail in the section ahead, (b) a train occupying the section ahead, (c) points unsafe, (d) speed excessive for a particular track. Fig. 7 shows a simple arrangement of circuits for one direction of traffic only, namely, from left to right of the Figure. A train on the ramps 1, 2 closes the circuit from battery 370 through the relays 371, each of which completes the circuit from the track batteries 377 to the opposite rails and the track relays 380, the armatures of which, if all sections of track are clear, complete the circuit from the battery 370 over resistance 387 to the track contacts 1, 2. The current in this circuit is sufficient to restrain the operation of the danger signals. Modifications of the circuits and apparatus on the track are described for single and double track working; polarized relays may be used both on the track and train. Manually operated switches 372 are provided for control by a signalman. Points may be fitted with apparatus connected up to a track ramp so that unless the points are home and locked the traincircuits are not energized to restrain a danger signal. Fig. 10 shows a track contact provided with means for protection against damage by hanging chains or couplings. The T-shaped contact bar 506 is bolted to a sleeper 505 supported on chairs 504, the bolts in both cases being covered by metal casings with inclined surfaces. A nose 517 protects the end of the bar 506. An apparatus arranged on the train and provided with means for stopping the train in case of excessive speed at fixed points on the track is shown in Fig. 14. This includes a relay 611 in series with two reversing switches, one, 614, moved bv connexions to reversing gear of the locomotive and the other 616, set by hand for up or down working along the track, and with contacts on a speed-controlled device 618 and contacts engaged by an arm 603 which is swung laterally of the track to a distance D determined by the displacement of the side face of a track contact according to the allowable speed. The circuit to the relay 611 is thus closed only if apparatus on the track and train is in proper order and the speed is not excessive. The relay 611 controls the circuit to the restraining magnets 52, 53 of the signal and stopping apparatus. Modifications of train apparatus include line clear signals and means for unlocking an enclosing cover over means for resetting the signal and brake restraining devices. The said cover is locked by a latch controlled by an electro-magnet energizable from an extension or auxiliary ramp.