Patent GB-550685-A (GB)
Title: Improvements in or relating to the panel type of control means for railway signalling systems
IPC: B61L25/08
Filed: 1941-03-10
Abstract: 550,685. Railway traffic control apparatus. DOWNES, D. G. March 10, 1941, No. 3239. [Class 105] In a railway traffic control system each point, signal, track-zone or traffic-control operation is identified with two or more symbols, preferably numerals, and the desired operation is selectively initiated by the closure in succession and in order of contacts composing the desired number, each contact bearing a single digit. The contact device may be an adaptation of the telephone dial, a multi-position switch, or as described a bank of digit keys. The contact device or keys may be mounted in any convenient position, for example on or near the usual panel diagram or on a separate panel or desk. Fig. 1 shows a layout diagram in which the signals are identified by two-figure numerals and the Specification described setting up a route from signal 23 to signal 22 by operating buttons numbered 2 and 3 in the order 2, 3, 2, 2, leading to selective energization of relay 23- 22RLR which is one of a number of relays, not shown, that may be similarly selectively energized. Fig. 3 shows four keys, 0, 1, 2, 3 used in conjunction with groups of relays A0, B0, C0, D0 ... A3, B3, C3, D3 and contact banks S0 ... S7 of a stepping selector switch of known type moved one step each time a magnet S is deenergized after being energized. The selector ensures that one relay shall be energized from each group in succession, the number of groups corresponding with the number of digist in the selective number. Each group contains relays numbered in agreement with the keys 0, 1, 2, 3. Operation of button 2 closes contacts 2a in a circuit over wire 4 and first contact of selector bank S2 to relay A2. At the same time closure of contacts 2b energizes relay D common to all the buttons and its front contact closes the circuit through magnet S which is de-energized when the button is released, moving the selector one step. This selector movement occurs each time a button is pressed and released. Similarly, operation of button 3 energizes relay B3 over the second contact of bank S3 and successive operations of button 2 energize relays C2, D2 over the third and fourth contacts respectively of bank S2. Front contacts of relays A2, B3, C2, D2 close corresponding stick circuits for the relays over a common wire 50 and bank S4, the arm 8 of which makes contact in all positions except that immediately preceding the home position so that the relays remain energized until the selector is subsequently returned home as described below. Other front contacts A22, B32, C22, D22 of the relays are arranged in series with relay 23-22RLR together with winding BR of a bell relay, conflicting route contacts, indicated generally at CRC and closed if conditions are safe for the route, and track relay contact TR1 closed when the track section is unoccupied. A stick circuit for relay 23-22 RLR is closed over front contact 64 thereof and cancelling button contact CB1. When relay 23-32 energizes, simultaneous energization of relay BR breaks the circuit of a bell BS at contact 78 and closes a circuit through a second bell relay winding BRS over the fifth contact of bank S7, so that the bell remains out of action. If, however, relay 23-22RLR and relay BR should fail to energize owing to contacts CRC or TR1 being open, the bell is operated over back contact 78 and bank S7, and continues to sound until the selector returns to home position which follows completion of the button operation by closure of the circuit of magnet S over the fifth contact of bank S5 and the usual spring contacts SC. When the first button has been operated and released a circuit is closed through lamp Lover bank S6 to indicate that the selector is no longer in home position. Should the signalman desire to return the selector to home position before completion of the button operation, that is before the fifth contact of bank S5 has been reached by arm 68, he presses resetting button RSB, thus energizing resetting relay RSR contact RSR1 of which then closes a branch from the lamp circuit over contacts SC and magnet S. Relay 23-22RLR is de-energized when the train enters the section by the opening of contact TR1 but may be de-energized if desired by the signalman pressing cancelling buttonCB to open contact CB1. The specification describes the resetting of the signal to normal on the de-energization of relay 23-22RLR over a back contact of that relay in the circuit of a signal relay, not shown. With a train on the approach track leading to the signal a time relay.is energized and its contact completes the signal relay circuit. With no train on the approach track the signal relay circuit is completed over closed approach locking control contacts in parallel with the contact of the time relay. A system is referred to in which only two buttons are operated and in which two sets of digit buttons coloured red and white, for example, may be provided, and effecting different operations involving the same signal. For example, operating white buttons 2, 1 clears signal 21, and operating red buttons 2, 1 clears signal 21 together with the next two signals ahead. Separate sets of buttons controlling different portions of the layout may be provided in a cabin for the use of two or more signalmen during busy periods and a master set controlling the whole layout for use by one man during slack periods.