GB390572A - A new or improved system for controlling the operation of railway points, signals and the like - Google Patents

Abstract

390,572. Interlocking railway signals and points. BRITISH POWER RAILWAY SIGNAL CO., Ltd., Windsor Works, Slough, Buckinghamshire, SIEMENS & GENERAL ELECTRIC RAILWAY SIGNAL CO., Ltd., Caxton House, GLENN, S. L., 3, Central Buildings, both in Westminster, and HORLER, F., Central House, Kingsway, London. Dec. 9, 1931, No. 34147. [Class 105.] Relates to electric railway-signalling apparatus in which the signals and points are controlled by switch devices operated by levers, pushes, or the like, and in which interlocking is effected by preventing the completion of a circuit to any conflicting signal or points although the levers are always free to be moved. According to the invention, each lever switch device has associated therewith an " interlocking" relay to control the contacts for operating the signal or points and the circuit to this relay includes a contact of its own switch device and contacts of other " interlocking " relays and of traffic-controlled devices so that the relay can only be energized when the conditions are correct. The " interlocking" relay may be a two-coil relay with interlocked armatures, or a polarized relay. To clear a signal for the passage of a train over a main line having a crossover, the cross-over must be at normal so that the contact slide N12 of the cross-over lever relay B closes its contact 12 whereby, on moving the signal lever SA over to close contact 4-5, the reverse coil R of the signal lever relay A can be energized to actuate its contact slides N<2>, R<2> to close the reverse contacts and so cause clearing of the signal. When the signal lever is returned to normal the coil N is energized to return the contact slides N<2>, R<2>. The economy contact X opens when armature N<1> is lifted but this armature is held up in known manner by a latch released only when the coil R is energized. The inoperative coil N or R is shunted by the lever bridging contacts 2-3 or 5-6 to prevent actuation by stray current. The lever may be held sufficiently firmly over in the reverse position against the action of a return spring by a permanent or electro magnet effective only when the signal or points have moved over and closed detector contacts ; the holding action is not sufficient to prevent manual restoration to normal.