GB311309A - Improvements in and relating to train control systems - Google Patents

Abstract

311,309. Associated Telephone & Telegraph Co., and Hudd, A E. Feb. 9, 1928 Track apparatus for stopping trains.- The operation of the brakes of a train is initiated by the action of magnets on the track on an armature which strikes and actuates mechanically a valve which may be reset either by the armature or by pneumatic handcontrolled means. The locomotive carries two releasing valves which co-act with track magnets on opposite sides of the track and are connected by reversing valves so that one serves to cause a partial brake application at a caution signal unless manually controlled within a predetermined time while the other causes a full brake application as soon as it is operated, and can only be reset after a time interval has elapsed. The track magnets at a distant signal consist of a number of permanent magnets A1 and a number of electromagnets of reversed polarity 131 which are placed a short distance ahead of the permanent magnets and are energized only when a train is over rail 49 and the signal is at danger to close a switch in the circuit. The train carries two receivers, one of which is shown in Fig. 3, which are connected alternatively by the reversing valve RV<a> to the caution brake application valve 18 and whistle 13 or to the full brake application valve 23. On passing a track permanent magnet A1 at a distant signal the polarized armature 2a is reversed and opens the valve 3<a> controlling the diaphragm valve 7a. At a distant signal the pipes 9 is put to atmosphere and the whistle valve 12 is opened to sound the whistle 13. At the co-operating electromagnet B1, if the distant signal is at clear, the armature 2a is reset and the valves are restored. If the signal is at danger, the valves remain open and the chamber 15 is charged after a given time to the pressure required to open the brake valve 18. The driver can reset the armature 2a by use of the acknowledging lever AL which, though the valve RVb causes air to enter the pipe 21, Fig. 5, corresponding to pipe 27, Fig. 3, and to draw the armature to its normal position. At a home signal the electromagnets EC are superposed in pairs on the pairs of permanent magnets PM so that when energized there is no effect on the receiver BR. At a danger home signal, the permanent magnets reverse the armature 2a and through the pipe 9a open the full-brake application valve 23. The armature 2a can be reset by the driver actuating the releasing lever RL, only after sufficient time has elapsed for reduction of pressure in the chamber RA.