Patent GB-418631-A (GB)
Title: Improvements in systems for the selective control of remote apparatus, more particularly for centralised traffic controlling installations
IPC: B61L7/08
Filed: 1934-03-22
Abstract: 418,631. Electric signalling and distant-control systems. GENERAL RAILWAY SIGNAL CO., Rochester, New York, U.S.A.-(Assignees of Powell, W. T. ; 413, Brownoroft Boulevard, Rochester, New York, U.S.A.) March 22, 1934, No. 9031. Convention date, March 22, 1933. [Class 40 (i).] In an electric selective remote-control system, more particularly for controlling and indicating the positions of railway points and signals, a plurality of outlying stations is connected to the central office by a control line and a plurality of return lines, selective control being effected by the transmission of positive and negative impulses over the control line and supervision by the transmission of stepping impulses over the control line to facilitate the selective connection in different combinations of the return lines at each impulse. Furthermore, during supervision each impulse may be subdivided so as to effect a sequential interconnection of the return lines to provide for further selective possibilities. Figs. 2 and 3 show the apparatus at the control station and Fig. 4 that at one of the outlying stations. The stations are interconnected by a " stepping " line wire S and two return line wires A, B, relay chains IV, IVP, 2V, 2VP, 3V ; IV<1>, IVP<1>, 2V<1>, 2VP<1>, 3V<1>; being provided at each station and adapted to be driven in synchronism by impulses over the line S. Control of apparatus at an outlying station is effected by the transmission of a code of + ve and -ve impulses over line S and return lines A, B in parallel, the code being determined by operation of the appropriate central office relay CD the contacts of which are jumpered to bus-bars PC, NC. Indications of the position of apparatus at an outlying station are transmitted by selectively associating the A, B lines with the " stepping " line at each step of the relay chains. This arrangement also facilitates duplex working of the system. Normal condition of system. Normally the line S is open circuited and lines A and B are connected in series with battery LB to maintain relays MA, MB energized. Control of apparatus at an outlying station. The operator initiates a cycle of operations for the selection of a particular outlying station and the transmission of the necessary controls to the selected station by positioning the necessary control levers and then actuating the " start " button SB which pulls up the appropriate code-determining relay CD. CD pulls up C which operates " start " relay STR to disconnect the series circuit over A, B and connect battery LB to line S and lines A, B connected in parallel. This operation constitutes a " conditioning " pulse which operates line relays F, F<1>. Relay F at central office energizes SA, SAP in sequence, the relay SAP de-energizing STR to terminate the pulse. During the pulse the first stepping relay IV is pulled up by FP. When STR releases, relay F releases to pull up the next chain relay IVP which pulls up 2V and also relays E, EP to again energize STR, which initiates the second pulse. This second pulse constitutes the " first " signal pulse and is terminated when relays IV, E, EP are released in consequence of the pulling up of STR. Release of EP releases STR and the second pause is initiated. During this pause IVP is released and relay 2VP pulls up over contacts of locked relay 2V to pull up 3V which operates E, EP and in consequence the relay STR to initiate the second signalling pulse. During this pulse IV is again pulled up and during the following pause IVP pulls up. The next pulse and pause release the relays IV, IVP and this method of pulsing the relays IV, IVP to control the relay STR is continued until relay E can no longer be energized over the back contacts of the stepping relays. When, in the arrangement shown, the relay E fails to pick up at the end of the fourth " signal " pulse, relays SA, SAP drop together with the operated stepping relays so as to restore the central office equipment to normal. The polarity of the impulses transmitted over the line S is determined by the relay CD the contacts of which are wired to the back contacts of the stepping relays IVP, 2V, 3V and to the " positive " and " negative " relays PC, NC. During the " pause " periods the back contacts of IVP, 2V, 3V are operated and consequently the polarities of the succeeding pulses are determined by the jumpering at the contacts of the CD relay. The pulses are transmitted to the remote stations and there operate relays F<1> in accordance with the polarities of the impulses. The relays F<1> operate the stepping relays in synchronism with the central office relays and effect selective con rols over circuits not shown. Supervisory signalling. Upon a change in the condition of apparatus at an outlying station the locking-circuit of relay CH<1> is opened and the relay released to pull up relay PLA<1> which opens the normally energized line circuit over lines A, B at back contact 100. Relays MA, MB are thereby released and FC pulls up to operate STR which energizes the line S to initiate pulsing in the manner previously described. A cycle of impulses is then transmitted over the line wires in the manner previously described with the exception that throughout the cycle relay NC is maintained operated and PC is maintained open in order that only negative impulses may be transmitted. Assuming signals are to be transmitted from the station shown in Fig. 4, a code is first transmitted to select a relay 7ST, Fig. 3, corresponding to the station so as to connect up indicating relays PO, 1PB, 2PB ready for operation in accordance with the positions of the apparatus at the station. The station code is characterized by the jumper connections from the bus-bars NS, 1S. 2S to the leads 205, 206, 207. The lock out relay LO<1> is operated during the " conditioning " pulse and during the first " pause" period following that pulse, i.e. when IVP<1> is up, relays PLA<1>, PLB<1> are pulled up over the jumper 205 to open the A, B lines. Slow release relay PLT<1>, which is also energized by the conditioning pulse, is released and after time delay releases PLA, but not PLB<1> since this is maintained operated over jumper 201. This time delay is longer than the pick-up times of office relays E, EP, STR so that STR fails to energize the S line and the pause is lengthened by the action of the PLT<1> relay. Relay EPT, Fig. 2, is prevented from operation and consequently relay PO is operated during the pause by reason of the operation of IVP, 2V<1>. If the wire 205 is left unjumpered (the condition at another station) relays PLA<1>, PLB<1> remain down during the first pause to that STR is effective immediately to energize the S line and produce a " short " pause period. This allows EPT to pull up and thereby prevent operation of PO to facilitate selection of another station relay. When PLA<1> drops at the end of the first pause, the first pulse is initiated over lines S, A and MA is pulled up MB remaining down. When 3V pulls up during the second pause station relay 7ST is operated. Various other selections may be performed during the first signalling pulse in accordance with the jumpering of the leads 206, 207 with NS, 1S, 2S bus-bars. Jumpering in this manner allows MA or MB to be operated continuously throughout the pulse or permits the relays to be energized sequentially for long or short periods during an impulse. The latter mode of relay operation 13 is accomplished by subdividing each pulse into three parts by the operation of relays SD<1>, SAP<1> during the sequential operation of the relay chains and operating the relays for two-thirds or one-third of the pulse. These different code effects operate relays MA, MB in a corresponding manner to effect operation of relays PO, 1PB, 2PB in different combinations to facilitate twelve selective possibilities for each step of the relay chain. Further selections are then accomplished by subsequent pulses. For example, the subsequent pause may be made long or short to produce selective operation of relay ITR, Fig. 3, in accordance with the marking or otherwise of lead 211 by track relay T<1>. Similarly three selections may be transmitted by the " points " relay in accordance with the marking of one or other or both of the leads 212, 213, the corresponding signals operating the signal relays 2IR, 3IR, Fig. 3, in different combinations. Lock out between outlying stations. In order to prevent more than one station obtaining access to the line during a cycle of operations, lock out means are provided at each station which are effective to give control of the line to the station nearest the end of the line. Two-way transmission. Relays C and FC operated respectively upon initiation of the control and supervisory codes may both be energized at the beginning of a cycle of operations. In consequence relay NC is prevented from permanent energization and permits selective conditioning of PC, NC busses in accordance with the operated CD relay. The following impulses applied to line S are + ve or -ve according to the control code and the pauses are controlled in accordance with the condition of the equipment at the signalling station. Specification 377,971 is referred to.