Patent GB-344712-A (GB)
Title: Improvements relating to automatic train control systems
IPC: B61L3/10
Filed: 1930-04-30
Abstract: 344,712. Train control systems. GENERAL RAILWAY SIGNAL CO., Rochester, New York, U.S.A.-(Assignees of Bodde, T. ; 1289, Genesee Park Boulevard, Rochester, New York, U.S.A.) April 30, 1930, No. 13340. Convention date, May 16, 1929. [Class 105.] Track apparatus actuating signals on and for stopping trains; electrical systems. automatic; audible signals.-Track apparatus for giving signals on and for controlling trains comprises an alternating current source on the train and a rectifier unit on the track which is connected one wav or the other to, or disconnected from, a track ramp in accordance with the signal and control to be given. The Figure shows an automatic signalling system with track sections each having a polarized track relay T and a track ramp TR with an associated rectifier unit 8 the connections of which are reversed by contacts 6, 7 of a relay RR controlled by the track relay T. Clear, caution, and danger positions of a track signal Z are given with the track relay energized normally, reversely, or de-energized. The rectifier circuit includes a signal arm contact 9. If a section J is occupied the track relay T<1> also opens the contact 10<1> in the line of the rectifier 8<1> and reverses the connection of the track battery 11<1> for the section I, the track relay T of which being reversely energized opens a contact 5 to de-energize relay RR the contacts 6, 7 of which drop to reverse the connection of the rectifier 8 to the ramp TR. The " signal at clear" circuit for the signal Z is also broken at the contact 5 but the " signal at caution circuit remains. The apparatus on the train comprises a turbo-generator G giving alternating and direct current; the alternating current in conjunction with a transformer 27 and the track rectifier provides pulsating current to operate a main relay MR of the polyphase induction type and the direct current actuates caution, clear and signal relays CA, CL, SR, which control a brake valve EPV and bell and whistle signals BL, W. Resetting and annulling keys RS, AN are provided. In the condition shown, the relays CA, CL are held by stick circuits over their own contacts and contact 21 controlled by the shoe 20, and the brake valve EPV is energized over shoe-controlled contact 22 and contacts of the relays CA, CL. The circuits are for relay CA: wire 36, shoe contact 21, wires 38, 39, its own contact 40 and lower winding, wires 43, 44; for relay CL : as above to wire 38, wire 47, own contact 48 and lower winding, wire 44; for brake valve EPV: wires 52, 53, contact 54, shoe contact 22, wire 57, contacts 58, 60 of relays CA, CL, normally closed contact 63 of annulling key AN and wire 64. When the shoe 20 engages a ramp TR in the caution state the track rectifier 8 is connected by the dropped contacts 6, 7 so that in the main relay MR a pulsating current flows in the winding 31 and a small alternating current, due to an opposed rectifier 32, in the winding 30. The first current' is a lagging one due to inductance but the second is in phase due to the high resistance of the rectifiers in opposition; the polyphase induction relay accordingly moves its contact 80 to the left. This picks up the relay CA (relays CA, CL having been de-energized by the shoe 20 opening the contact 21) over wire 81, shoe contact 23, wire 82, contact 80 at the left, and wires 83, 43, 44 ; when the shoe drops on leaving the ramp, the relay CA is held by its stick circuit. Relay CL however remains deenergized so that its contact 60 is dropped and a whistle W is energized thereover from the contact 58 in the circuit to the brake valve EPV which is now broken at contact 60 so that a brake application begins. This can be annulled by depressing the key AN to close a contact 88 whereby relay CL is picked up from wire 38 over wires 87, 90 and held by its stick circuit so that the brake valve EPV is energized as before. Should the key AN be depressed more than say 15 seconds a dashpot-retarded contact 63 in the circuit to the brake valve opens. In the danger condition the track ramp is disconnected from the track rectifier so that the main relay MR is not energized and therefore the relay CA is not picked up on leaving the ramp. Accordingly both relay contacts 58 and 60 are open so that the brakes are applied but without the whistle signal W. If the driver is alert he may depress the not readily accessible resetting key RS to pick up the relays CA, CL over contacts 92, 93 and if he returns it at once to restore the contact 54 the brake valve EPV is again energized. In the clear condition of the track ramp the track rectifier 8 is connected at the front contacts 6, 7 so that in the main relay MR the large lagging pulsating current now flows in winding 30 and the small in-phase alternating current in winding 31 with the result that the contact 80 moves to the right. Relays CA, CL, SR are accordingly picked up by current in their upper windings from shoecontrolled contact 23 so that the brake valve is maintained energized. The signal relay SR has a lower winding 102 short circuited by its contact 103 so that it is maintained energized a short time to sound a bell BL over its contact 101.