Patent GB-158966-A (GB)
Title: Improvements in train control systems
IPC: B61L3/10
Filed: 1919-11-07
Abstract: 158,966. Haddan, R., (Regan, J. B.). Nov. 7, 1919, Electrical systems, automatic; track apparatus for stopping trains. -A reversing switch, controlled automatically by traffic on the track ahead, determines the polarity of current supplied through a track ramp to a polarized relay on a train which is in a normally closed train carried circuit but at a ramp is included in a partial track circuit by the movement of a switch carried by the collecting shoe. The polarized relay controls train stopping means and a speed-controlled contact is arranged in series with one of the circuits closed by the relay so as to apply the brakes only if the train-speed is higher than a predetermined maximum allowable under the existing conditions. Relays for detecting defective circuits on the track are provided to produce danger indications if ramp or semaphore circuits fail. The track circuits for three sections AA, BB, CC are shown on Fig. 2. A train T' on section AA deenergizes the track relay TA, and the home-control relay HA opens the caution circuit of the semaphore 20A at contact 5A', of the ramp 12A' at contact 21A, of relay DA controlling clear position of the signal 20A, and of relay DB which controls the clear position of signal 20B. Signal 20A consequently goes to danger and signal 20B to caution. Section BB being clear of traffic the track relay TB and home control relay HB are energized and battery B2B is connected to the ramp 12B'. Similarly, relays TC HC are energized and also DC which causes signal 20C to move to " clear," and reverses the connections of the battery B2C to the ramp 12C<1>. Thus the ramp 12A<1> is not energized and ramps 12B<1>, 12C<1> are energized but are of opposite polarity. The train apparatus shown in Fig.- 1 includes a polarized relay R in a normally closed circuit from battery B, over armatures e, f, and contacts 8, 10 on the shoes S, S'. The brake controlling magnets A, B are in series with the battery B and armature g. At a " clear " signal 20C, the shoe S' engages the ramp 12C<1> and this circuit is opened at contacts 10 and current passes from the battery B2C on the track, to ramp 12C<1>, shoe S' to relay R which remains energized, and the train brakes are held off. At a caution ramp 12B<1> the relay R receives current by a similar circuit but of reversed polarity and its armatures are reversed and remain reversed after passing the ramp since the armatures e, f reverse the connections of the battery B; the armature g is also reversed and the magnets A, B are put in circuit with the speedometer contact F so that the brakes are applied if and so long as the speed exceeds that at which the contact F is closed. A relay A16 is included in a circuit which passes from end to end of the ramp 12A' so that if the ramp is broken, the relay is de-energized and opens the circuit of the relay HB of the rear section, thereby causing danger conditions of both the signal 20B and the ramp 12B<1>. A contact 13A on the semaphore 20A controls relay DB, thus ensuring correlation of the signal 20B and ramp 12B<1> with the signal 20A. A relay A17 in connection with the ramp 12A<1> controls the signal 20A so that if the ramp circuit is defective the signal 20A moves to danger. A switch C, Fig. 1, is provided for resetting the relay R after the passing of a ramp in the danger condition.