Patent GB-583217-A (GB)
Title: Improvements relating to railway traffic controlling apparatus
IPC: B61L7/08
Filed: 1942-11-06
Abstract: 583,217. Railway-traffic control systems. TOMLINSON, A. V. (Union Switch & Signal Co.). Nov. 6, 1942, No. 15707. [Class 105] In a railway-traffic electric controlling system for controlling traffic in both directions over a single-track stretch divided into insulated track sections, operation of a lever at the control office selectively energizes a traffic direction relay at that field station located at the desired entrance to the stretch, pick-up of the relay results in an impulse of steady energy being cascaded from entrance to exit, where its receipt provides indication at the office that the stretch is unoccupied, and in the supply of master code at the exit end, the code being cascaded to the entrance end where its receipt clears the head-block entrance signal. The code also results in the pick-up of the proper directional stick relay at intermediate locations. As the train progresses and clears each tracksection master code is applied thereto at the leaving end resulting in supply of feed-back code at the entrance end of the stretch, so that the feed-back code is relayed in succession over the track-sections as they become vacated and thus follows the train and results in the cutting off of master code as the train passes completely out of the stretch. This train-following code arrangement is described as the principal feature of the invention. Absence of master code at the exit end results in the de-energization of the track section at that end, the de-energizing action being cascaded to the entrance and so that the system is automatically restored to normal. The invention is described as an improvement on the system described in Specification 563,284. Figs. 1a, 16, 1c show a single track between passing sidings S1, S2, divided by insulating joints at locations D, E, F, G, H into track sections 1-4. Normally lighted head block signals ESD, WSH at stop position for eastbound and westbound traffic respectively are situated at sidings S1, S2. Intermediate signals ESF, WSF at location F are normally de-energized, as are also the coded track circuits with the exception of the neutral switch track circuits 1, 4 for the OS sections at the sidings. The specification traces in detail the circuits involved in the following typical operation. To permit an eastbound move through the single-track section the operator moves lever ESL at the office from its neutral to its R position and presses the usual starting button, not shown. Code is thereby transmitted to the field-station apparatus at location E to energize eastbound traffic relay 2EHSR. This results from energization of terminal 85. The coded line circuit comprises only one pair of line wires, but broken lines to each of the terminals 85, 86, 91 &c. are shown for descriptive purposes, the numbering of the terminals and the results of their energization being as described in Specification 415,787. Pick-up of relay 2EHSR opens the circuit of relay 2EBHSR but during release time relay 2ECTPR is picked up for a time over front contacts 28, 27, 29 and thus connects track battery TB across the track to transmit a steady impulse eastwards. This energizes relay. 2WTR at location F to close the circuit of relay 3ECTPR and so cascade an impulse from battery TB at that location into section 3. At location G relay 3WTR is thus picked up to close the energizing circuit of relay 3WFSA. When the impulse of steady energy ceases due to release of relay 2EBHSR relay 3WTR releases and establishes a momentary pick-up circuit for relay 3WBSR, which picks up and closes contact 36a to energize terminal 89 resulting in the lighting of eastbound traffic lamp EB on the office panel OF to indicate that the stretch is unoccupied. Pick-up of relay 3WBSR also closes contact 38 to operate the code transmitters 180CT and 75CT. As Signal ESG indicates " stop " and its home relay 4EHR is de-energized, 75 code is supplied to operate relay 3WCTPR and thereby transmit 75 code from battery TB at location G to section 3. Relay 3ETR at location F follows this code and energizes decoding transformer 2EDT in known manner, thus energizing relay 3EHR to close the energizing circuit of eastbound directional stick-relay 3ED. Pick-up of relay 3ED connects the decoding unit 180DU and the 180 code decoding relay 2DR with the eastbound decoding transformer 2EDT over its front contact 37 (rather than with the westbound decoding transformer 2WDT). This use of a common decoding relay for either direction of traffic movement is as described in U.S.A. Specification 2,244,901. Relay 3ED remains picked up over a stick circuit including front contacts 63, 64 of relays 3EHR, 3ED, and energizes code transmitters 75CT, 180CT at location F. 180 code now operates relay 2WCTPR which applies that code to section 2. This code is received and followed by relay 2ETR at location E, thus energizirig decoding transformer 1EDT. Detecting relay 2ECDR and decoding relay 2EDR respond, pick-up of relay 2EDR causing head-block signal ESD to clear. Red signal indication lamp 60 on the office panel goes out, and green lamp 61 is lit. The train may now proceed over approach section 1 into the single track stretch. Presence of the train in this section is indicated by lighting of lamp 1OSL. The operator may now restore lever ESL to neutral position. When the train leaves section 2 and passes location F 75 master code is transmitted from location F to location E, by operation of relay 2WCTPR and feed-back code is transmitted from E to F, i.e., in the direction of train travel. The manner in which this operation is performed is wellknown and described, for example, in U.S.A. Re-issue Specification 21783. Relay 2WTR follows the feed back code. The track relays of the system (including relay 2WTR) are provided with stick windings which improve their operation by the relatively short feedback impulses, as described in U.S.A. Specification 2,172,893. When the train clears section 3 relay 3ETR starts to operate on 75 master code and relay 3ECTPR is energized intermittently by transformer 3EIT to transmit feed-back code through section 3. Relay 3WTR follows the 75 feed-back code and thus energizes detector relay 3WCDR. This releases relay 3WBSR to de-energize the code transmitters and cut off master code at location G, followed by cut-off of master code from section 2, so that all track circuits of the single-track stretch are de-energized. At the same time traffic light EB on the office panel goes out, indicating that the system is deenergized and ready for an opposing move if desired. In the event of failure of the C.T.C. control equipment, the system is operable under manual control by, push-buttons PB1, PB2 at location E. The Specification also describes in detail a modified system operating in a manner generally similar to that of the above-described system, except that advance pick-up stick relays are used at intermediate locations to provide for following moves in place of the directional stick relays of the above system.