Patent GB-351039-A (GB)
Title: Improvements in or relating to train control systems
IPC: B61L3/12
Filed: 1930-03-17
Abstract: 351,039. Fluid-pressure brakes. ASSOCIATED TELEPHONE & TELEGRAPH CO., 1033, West Van Buren Street, and HUDD, A. E., 947, West Van Buren Street, Chicago, U.S.A. March 17, 1930, No. 8596. [Class 103 (i).] A train control and cab signalling system comprises two track elements arranged at equal and opposite distances from the mid line of the track so as to act substantially simultaneously on two receiving elements similarly arranged on the locomotive which each include a member movable independently of the other to act on a device for effecting the braking and cab signal and the arrangement is such that if both members are moved substantially simultaneously that operation is not affected. The receiving elements may each comprise two magnetic flux collecting plates acting on an armature and the two track elements may comprise a permanent magnet and an electromagnet energized when the wayside signal is at clear. A train control and cab signalling system as above is shown provided at a distant signal while at the stop signal the train control system forming the subject-matter of Specification 351,071, [Group XXX], is provided. The apparatus shown gives a siren signal and a partial brake application at the danger position of the distant signal D, and an emergency brake application at the stop signal S at danger. A whistle signal is given if the distant signal is at clear. The track elements, Fig. 1, consist of longitudinal permanent and electromagnets A, B at a distant signal D and a central element C with longitudinal permanent and transverse electromagnets at the stop signal S ; the electromagnets are energized when the signals are at clear. The receiver elements Z, Y, X comprise flux collecting plates arranged similarly to the magnets of the track elements A, B, C, to actuate armatures which move thin phosphor bronze strips 63 which act as slide valves normally closing venting ports 92 in vacuum piping 58, Fig. 4; the armatures are returned by plungers 8 which are opened to vacuum piping 57 when acknowledging keys are operated to annul the automatic brake and cab signal. This magnetically operated. slide valve forms the subject-matter of Specification 351,072. The locomotive apparatus shown in Fig. 6 comprises a valve 70 for partial brake application which is provided with two pistons 78, 79 subjected to vacuum but with pipe connections 47, 44 to the receiver elements Z, Y so that if both elements are simultaneously actuated the valve 70 being balanced and centrally located by springs does not move and the brakes are not applied, only a whistle 35 sounding by the entrance of air through the pipes 72, 73 into the casings of the magnetic receiver elements. Should only one receiver element be energized the valve 70 is unbalanced and moves to open the train pipe 43 for a brake application, the entering air actuating a siren 28. On moving an acknowledging key APE the armature re-setting plungers 8 are connected to a vacuum reservoir V through pipes 48, 80 and restore the armature slide valves whereby the driver resumes control. At a stop signal at clear the transverse track electromagnet is energized and the flux collecting plates 4, 5 of the receiver element X therefore prevent the movement of the armature 3 by the other flux collecting plates 6, 7 which are simultaneously influenced by the track permanent magnets ; when the stop signal is at danger the track electromagnet is not energized so that the armature 3 is moved by the permanent magnet influenced plates 6, 7 to open the venting port 92 whereby a diaphragm actuated valve 66 is opened to vent the train pipe 43 for an emergency brake application. A second acknowledging key APF, accessible only when the train is stationary, can be moved to restore the apparatus. Both acknow. ledging keys APE, APF have ports 38, 14 so that, if wilfully held over they continue to vent the train pipe 43. The partial braking control apparatus E acting in conjunction with the distant signal can be detached from the train pipe, a plug being substituted ; the apparatus E may comprise diaphragms instead of pistons to control the braking and audible signal valves.