Patent GB-581058-A (GB)
Title: Improvements in railway traffic control and indication apparatus
IPC: B61L7/08
Filed: 1944-09-13
Abstract: 581,058. Railway signalling apparatus. WESTINGHOUSE BRAKE & SIGNAL CO., Ltd. Sept. 13, 1944, No. 17474. Convention date, Oct. 9, 1943. [Class 105] For the continuous transmission of an operating control from a central office to a waystation and of a return indication to the office from the .way station over a single line-circuit, signal-indication code current pulses (of normal or reverse polarity and different interruption rates for the different signal indications) cause the operation of a codefollowing relay at the office which in turn causes control pulses to be applied to the line-circuit during the " off " periods of the indication code thereby to effect the operation of the traffic controlling device at the way station. Fig. 1a shows a simple way station, Figs. 1b and 1c show two separate line-circuits to the office and Fig. 1d shows the indication panel at the office. The way station has East and West bound signals 2RA-B, 2LA-B, a diverging points operated by a points machine IW and having contact arm 5 to energize a points normal (or reverse) repeater relay IN (or IR), and track sections 2RT, IT, 2LT with track relays 2R, ITR, 2L. The line-circuit 11 Fig. 1b, serves for the transmission of a control for operating the points and for the return indication of the signal aspect and approach section track occupations ; the line circuit 29, Fig. 1c, serves for the transmission of a signal clearance control and for the return indication of the points setting, of the points being locked against operation, and of detector section track occupation. The points and signals are controlled by the panel levers 1V, 2V, Fig. 1d. With the signal lever 2V in its n position (signals at danger) the signal control relays 2LH, 2RH at the way station will be de-energized whereby relays 2LP, 2RP denoting signals at stop will be energized. Accordingly, at the way station positive battery FB is applied to line wire 11, Fig. 1b over front contacts 6, 7 of the relays 2RP, 2LP, coding contact 8 (operating at 75 interruptions a minute) and front contacts 9, 10 of track relays 2L, 2R to energize polar biased, code-following relays 2PS, 2HP at the office, but only the relay 2PS responds to the positive polarity so that current from a source OB is fed over back contact B of the inoperative relay 2HP, vibrating contact 14 of the codefollowing relay 2PS, to the two halves of a midtapped transformer 2RF whereby a polarbiased, code-following impulse relay 2P is energized to operate its contact 12 to its front point each time the relay 2PS or 2HP drops between the pulses of the indication current. During such closures of the front contact 12 of the code-following impulse relay 2P a control current is applied to the line wire 11 from the office. With the panel points lever 1V at the n position closing contact N20 this current is of positive polarity and energizes polar biased points control relays 1NW, 1RW at the way station over the coding contact 8 on its back point. With positive control current only the relay 1NW responds and the closure of its contact 23 energizes the polarized points control relay 1WR to its normal position which would energize the points machine 1W over contacts 1WR-43, 1WB-44 to set the points normal if not already in that position. It will be noted that the positive indication current caused the energization of a relay 2PR included in the circuit over back contact 13 of relay 2HP and front contact 14 of the relay 2PS; a front contact 38 of such relay 2PR lights a panel lamp 2PK denoting signals at danger. Entry of a train into section 2RT would drop track relay 2R to open its front contact 10 and close its back contact 10 whereby the signal indication current of positive polarity would now be applied to line wire 11 over arm 39 of a 180 interruption-rate coder 180CT, front contact 40 of track relay 2L, and back contact 10 of track relay 2R. Current applied to the transformer 2RF at this interruption rate by the contact 14 would energize a resonant decoding unit 180DU and decoding relay 2RD ; a front contact 41 of this relay 2RD would light panel lamp 2RK to show track occupation. If the panel signal lever 2V had been set to the f position to clear the West bound signal (by positive control current over line wire 29 operatively energizing a polar biased signal control relay 2LR to effect in turn the energization of signal control relay 2LH and de-energization of relay 2LP) a negative indication current would have been applied to the line wire 11 from back contact 7 of relay 2LP which would have operatively energized relay 2HP and not 2PS so that relay 2PR would not have been energized and accordingly panel lamp 2LVK denoting Westbound signal cleared would have been lit over back contact 38 of relay 2PR and lever contact 50 in its f position. The indication of the points setting is effected in a similar manner by positive or negative pulses, over the line wire 29 effecting the operation of a polar biased relay 1NP or 1RP with consequent energization of a relay 1NR or 1RR to light a panel lamp 1NK or 1RK; indications of the points being locked against operation or of the presence of a train in the detector section IT is given by a change in the interruption frequency, appropriate panel lamps 1LK or 1K being lit over contacts of the decoding relays 1LD or 1TD.