Patent GB-518769-A (GB)
Title: Improvements in traffic controlling systems for railways
IPC: B61L19/06
Filed: 1938-08-30
Abstract: 518,769. Railway control systems. GENERAL RAILWAY SIGNAL CO. Aug. 30, 1938, No. 25427. Convention date, Dec. 18, 1937. [Class 105] Route. setting apparatus in which entrance and exit buttons are operated to set up the route and clear the signal is arranged so that the entrance button can be differently operated according as it is desired that the route circuit should remain in operation'or not after a train has passed. Other different operations of the entrance button allow a call-on signal to be given with or without a de-energization of the route circuit when a train passes. The entrance button is briefly ,depressed. when it is desired that passage of a train shall de-energize the route circuit but is rotated clockwise if the route circuit is to remain in operation; for a call-on signal with the route circuit remaining in operation the entrance button is rotated anticlockwise. If the route circuit in all cases is to be de-energized by a passing train then the apparatus is modified as shown in Fig. 3, where the call-on signal requires the entrance button to be rotated anti-clockwise and briefly depressed. Referring to Fig. 1 and assuming the main signal 10A is to be cleared for the.route over the points TS at normal and that the route circuit is to be de-energized on passage of a train then the entrance button 10NB is briefly depressed whereby a relay 10NR is picked up by a circuit +ve, front contact 20 of track relay 2T, commutator contact 21 of the entrance button in the non-rotated position. depressed contact 22, and upper winding of the relay 10NR; the'relay 10NR remains energized over its own front contact 23, contact 22 in the normal position, and contacts 21, 20. A front contact 24 of the relay 10NR applies.potential to the route network and when an exit button 12XB is operated a relay 12XR is picked up and then stuck over its own front contact 42. A front contact 43 of the relay 12XR energizes a relay N to set the points TS to normal and a front contact 47 energizes a signal relay 10G over a front contact 48 of a relay NCR (denoting points at normal), a back contact 49 of a relay 10XR, and a front contact 50 of the relay 10NR. The signal 10A is cleared by a circuit from +ve, over a front contact 51 of the relay NCR, a back contact 30 of a relay 10CR. a front contact 52 of the relay 10G and a front contact 37 of the track relay 2T. The opening of the front contact 20 of the track relay 2T by a train will open the stick circuit of the relay 10NR which will then remain dropped so that the route circuit becomes de-energized. If it is desired that the route circuit remain in operation then the entrance button 10NB is rotated clockwise to close its commutator contacts 25, 26 whereby a lower winding of the relay 10NR is directly energized so that the relay 10NR is not dropoed when a train passes and thus the route circuit remains in operation ; the signal 10A goes to danger whilst the contact 37 of the track relay 2T is dropped. The two windings of the relay 10NR are arranged differentially to ensure that the relay drops when the entrance button is returned from the clockwise position ; if the relay 10NR has not opened its' contact 23 then its upper winding receives current but the flux is reverse to that of the lower winding and therefore the flux passes through zero and ensures the dropping of the relay. A call-on signal is given by rotating the entrance button anticlockwise to close its commutator contacts 25, 27 whereby a relay 10CR is energized. A front contact 28 of the relay 10CR and a back contact 24 of the relay 10NR then energize the route circuit (when an exit button is depressed) and the signal relay 10G is now energized by a front contact of the relay 10CR instead of by the contact 50. The call-on signal 10C is cleared by a circuit over a. front contact 29. of the relay 10CR and a front contact of the relay 10G. The track relay 2T has a repeater relay 2TP which permits the relay 10NR to be picked up while a train is still on the section. In the arrangement shown in Fig. 3 the route circuit is always deenergized when a train opens the contact 20 of the track relay 2T since the relay 10NR is energized by a stick circuit only. For a call-on signal the entrance button must be rotated anti-clockwise and briefly depressed. The operator can de-energize the route circuit by briefly pulling out the entrance button 10NB since this opens the contact 22 in the. stick circuit. The entrance button is provided with red and white lamps; the red lamp RSK is steadily lit over back.contacts 53 ... 55 when the apparatus is unoperated but is flashed over flasher contact 56, front contact 53 or 54, and back contact 55 while the route circuit and signal relay circuits are being set up ; the white lamp WSK is steadily lit over front contact 57 when the signal relay 10G is energized. Specification 513,515 is referred to.