Patent GB-366919-A (GB)
Title: Improvements in or relating to electric signalling or remote control systems
IPC: B61L25/04
Filed: 1930-11-06
Abstract: 366,919. Electric signalling systems. STANDARD TELEPHONES & CABLES, Ltd. and GRIFFITHS, J. B., Columbia House, Aldwych, London. Nov. 6, 1930, No. 33369. [Class 40 (i).] A train describing system comprises a control station and a number of other stations along a railway track each with means for storing a number of descriptions and displaying one or more of them, the arrangements being such that a description is received simultaneously at a number of stations. The descriptions are transmitted as trains of current reversals over a pair of conductors a, b, Fig. 1, which shows the receiving and displaying arrangements at a station. Each station has an impulse responding relay A connected across the conductors a, b and the trains of impulses set a register LR which marks and controls the setting of the first idle one of a set of storage devices 1 .. 7, the first or more of which are associated with display devices. In early morning when the storage devices at all stations are empty, the first few descriptions are sent simultaneously to all stations, but as removal of a description depends on passage of a train past the station, the storage devices at stations some distance down the line are soon filled up and it is necessary to stop simultaneous transmission to all stations. For this purpose, the stations are arranged in sections, and when the station at the end of say the first section has received a predetermined number of descriptions (five as described) a relay contact D is made and operates relay LC2 to open the outgoing line. When the next train passes this station, description in storage device 1 is removed and all other stored descriptions move up to the preceding storage device, and the description transferred from 6 to 5 is sent out by a retransmitter RET. Descriptions may be interpolated at any station, and this may be done by a sender SS connected to the signalling line if less than five descriptions are stored at the interpolating station, in which case the descriptions are stored in normal manner at this station and at succeeding stations. If more than five descriptions have been stored, relay R is operated and the sender is connected to a special register IR which marks and sets a storage device LS. When the normal storage devices are in such a condition that the description to precede the interpolated one is in device 5, relay DD is operated by key TK so that the next description to move into 5 will be from LS and not from 6. At the same time relay LC1 is operated to open the line and prevent backward transmission. There is an individual marking wire from register LR for each description and Fig. 1 shows two sets of storage devices 1 .. 7 for fast and slow tracks respectively so that the register LR automatically marks the correct set of storage devices ; goods trains on either track may be indicated by a signal lamp. For one-way working, two impulsing conductors and a pair of guard conductors for preventing simultaneous transmission from two or more stations are required. For two-way working, two pairs of impulsing conductors and two individual guard wires with a common return may be used. A single wire circuit may be used for impulsing. A stored description may be cancelled from a preceding station by transmitting a cancel code individual to the description. A special warning signal may be given to certain stations (signal cabins) in connection with particular trains, and for this purpose the first storage switch at a preceding station is so wired to a special transmitter that when a particular train passes, a code is sent out in response to which the register-markers at the signal cabins give an audible warning. The storage switches are driven from a common power drive which also drives a generator for supplying current to other equipment, and these switches may be rotary switches with terminal banks with a level for each of the possible stations to be displayed in addition to the marking levels by which they are set. The lamp corresponding to any particular station is connected to the necessary terminals in a level so that in any one position of the switch a number of stations at which the train is to stop are displayed. A switch of the sequence switch type may also be used, and in order readily to change the descriptions to be shown in any position of the switch, the usual cam formation may be replaced by a number of cam bars parallel to the switch shaft and detachably secured in peripheral slots in discs carried at the ends of the shaft. The sequence switches are also provided with wipers and terminal banks for setting them from the markers and, if required, for giving a simple description of a train in a signal cabin in addition to the more detailed description for a platform indicator derived from the cams. The Provisional Specification describes somewhat different storage arrangements in which any incorrect last sent description is cancelled by dialling " O " or, in the case of a key sender, pressing the cancel key. When fast and slow tracks are provided for a different cancel signal is used for the two tracks. Register-marker, Fig. 4. The first digit repeated by relay A operates counting chain C1 .. C5 from which the record is transferred to register HM1 .. HM5 associated with a relay HC operated if the digit exceeds 5. The second and third digits are then taken by chains C1 .. C5 and C6 .. CO respectively. The record is then transferred to a rotary switch comprising ten 100-point levels SBM, FBM, &c. and two control levels BFT, BFU. When the line circuit is closed A, P1, P1R, DM1, CC1 pull up in turn and P2, P2R are also operated. C5 in the counting chain operates and locks dependent on C1 which operates on the first impulse, locks dependent on C2, and makes C5 dependent on the impulse lead 1W so that C5 releases at the end of the impulse. DC1 now pulls up and connects CC1 to the impulse lead so that this relay holds during the train. Succeeding impulses operate and release the counting relays in turn and if C1 is operated a second time (digit exceeds 5), HC pulls up. During the inter-digital pause, CC1 falls back and the HM relay corresponding to the operated counting relay pulls up, locks dependent on P2R, releases DC1 and the operated counting relay. The operated HM relay energizes one of the ten wiper-choosing relays SM, FM, &c. Relay DM1 falls back slowly and operates DM2 which again connects ground to the counting chain to operate C5. The counting chain C1 .. C5 takes the second digit in a similar manner except that TC1 now operates if the digit exceeds 5. On the relapse of CC1 at the end of the train, RC transfers the impulse lead to the second chain C6 .. CO, and holds P1. The relapse of CC1 also marks a tens terminal in the bank BFT of the rotary switch, and operates clutch relay CL whereupon clutch CLU operates and the switch rotates to the marked terminal and CS1 operates to release the clutch and also relays P1, P1R so that the first counting chain returns to normal. The third digit passes to the second chain C6 .. CO which when CC2 relapses after the train, marks units terminals in the groups in bank BFU. Relay CC2 also releases CR2 which operates clutch relay CL so that the switch moves on to find the terminal marked in BFU in the group determined by the setting of the switch for the second digit, whereupon CS2 operates, releases the clutch, and energizes F which grounds the wiper selected by the first digit to mark one of the 1000 marking terminals. Relay A is eventually released and when the receiver described in the next paragraph has taken the description, ground will be removed from wire H and the circuits will return to normal. Receivers. The receiver shown in Fig. 2 comprises the first and one of a number of succeeding storage devices at a station or cabin for displaying descriptions of trains on the fast track with discrimination between passenger and goods trains. The storage switches have 100-point levels and provide for 200 descriptions with the aid of a wiper-choosing relay. The banks Ba are multipled together and to two marking levels of the marker, Fig. 4, so that terminals in this particular set of receivers are marked if the first digit is say 2 or 3. Relay BR is operated from the point BF in the marker after the relapse of CR2 and before the operation of F. BR locks up and grounds H, and when F, Fig. 4, pulls up to complete the marking it grounds point C, Fig. 4, to operate clutch magnet M1, Fig. 2, so that the receiving switch rotates to the terminal marked in Ba. The marking ground operates T1 (lower) which locks over its upper winding, releases magnet M1, releases BR to release the register-marker, and operates TR1 which lights indicator lamps over Be, Bf or Bg, Bh according to whether wiper-choosing relay PG1 is operated or not. Slow-to-operate relay D1 pulls up to transfer the incoming leads to the next storage switch. Relay PG1 which is operated over JF, Fig. 4, by relay HM3 is also arranged to operate a "non-passenger" lamp. If the description is one that is not to be taken by the fast-track receivers, there will be no marking in banks Ba and when the switch moves off normal, DC operates over bank Be and marks the home multiple of the switches in bank Ba so that the switch goes home. T1 operates as before but its locking circuit is opened by L1 operated in the home position so that when BR falls back the circuit becomes normal. Track control of receiver. It will be assumed that a number of descriptions have been stored in the set shown in Fig. 2. When a train operates track contact C1, RC1 pulls up and operates S1 which energizes RC2 and locks dependent on S2 in the next switch. T1, TR1 fall back and the lamps of the first receiver are extinguished but D1 is held. The terminals of bank Bb of the second switch are jumpered to those of Bc in the first switch and since relay S1 has grounded the wiper of Bb (second switch) and operated clutch