Patent GB-887751-A (GB)
Title: Automatic ctc system
IPC: B61L7/08
Filed: 1959-12-08
Abstract: 887,751. Control traffic control systems. GENERAL RAILWAY SIGNAL CO. Dec. 8, 1959 [March 12, 1959], No. 41672/59. Class 105. In a C.T.C. system for the control of signals and points at the ends of passing sidings on single-track railroads or analogous layouts, the initial setting of the signals &c. for train movements such as " meets " or " passes " results from a manual operation which also conditions apparatus by which subsequent settings to complete the movements are automatically controlled by the movement of the trains into and out of track circuits situated at the siding ends. The manually conditioned relay and circuit means which in response to the train movements completes the signal &c. settings may be positioned at the control office or located in the field. In the description of the invention communication between office and field station, Figs. 3A and 3B (not shown), is by means of the time code system disclosed in U.S.A. Specification 2,399,734, and the master control panel arrangement in the control office, Fig. 2 (not shown), is similar in principle to that disclosed in Specification 803,114 and includes means for selecting a particular siding, switch means for manually controlling train movements into and out of the sidings and switch means for initially setting and conditioning the signalling means associated with the selected siding for a " meet " or " pass '' movement. Where a " meet " has to be arranged, e.g. at siding A, and the east-bound train has to take the siding the operator selects the siding by operation of a push-button whereby a group selection relay A-GSN, Fig. 7, is operated. This Figure indicates part of the control office relay and circuit arrangement associated with the west end of siding A when the conditioning means are situated at the control office. To enable the trains to execute the " meet " movement the signals and points at the west end of the siding are initially set to clear eastbound and reverse respectively and when the eastbound train has taken the siding the signals and points are subsequently changed to clear westbound and normal to allow the westbound train to proceed. A self-restoring " meet " switch is operated to EB (eastbound to siding) whereby relay AW-M energizes via switch contact 112 and F.C. (front contact) 114 of relay A-GSN, magnetic stick relays 1W and 2-3D are actuated to their right-hand positions via circuits through switch contacts 131 and 132 respectively and store respectively the initial points and signal requirements, relay W-CH picks up over f.c. 120 of relay AW-M and locks over (back contact) b.c. 40 of relay W-LC. When relay W-LC energizes over b.c. 56 of relay LCS code signals are transmitted from the control office to the field station, these comprise a station selection code transmitted via f.c.'s 57, 58 and 59 (see Fig. 6B, not shown), of relay W-LC, a signalling code via f.c.'s 67 and 68 of relay W-LC and contacts 79 and 80 of the signal stick relay 2-3D and a switch or points code via f.c. 69 relay W-LC and contact 81 of points magnetic stick relay 1W. At the end of the code transmission relays W-LC and A-GSN release. The code selects the field station at the west end of siding A, Fig. 4, and the signal and points code energize respectively the easterly direction clearance relay 2RGZ and the points reverse relay 1WZR. The points ITW is switched to and locked in its reversed position by switch machine ISM and reverse points correspondence relay 1RCR operates. In addition, with the points in reverse position, signal 2B is cleared for entry of the eastbound train into the siding and a signal monitor relay 2M is deenergized. At the same time a similar arrangement associated with the east end of the siding initially sets the east end points to normal and the signal is cleared for westbound movement. The track relay 1T, signal monitor relays 2M and 3M and the points correspondence relays relays 1NCR and 1RCR are effective to transmit code indications of their respective conditions to the control office. As the eastbound train enters the track section ITS track relay IT drops, opening its f.c. 328 before b.c. 327 of slow-release repeater relay 1TP is closed, whereby the stick circuit of relay 2RGZ opens, dropping the relay and placing signals 2A and 2B at stop. In addition, the release of the track relay is indicated in the control office by the actuation of the contacts of relay 1TK to the left-hand position. Relay 1TKP energizes over f.c. 142 of relay AW-M and via contact 150 of relay 1TK either relay 3-2LD or 2-3RD is energized, depending on the setting of the magnetic stick relay 2-3D and either relay 1WN or 1WR, depending on the position of relay 1W, in this case relays 2-3RD and 1WR energize. As the eastbound train fully enters the siding and passes out of track section 1TS, relay IT picks up and at the control office relay 1TK is actuated to the right and de-energizes slowrelease relay 1TKP. Before relay 1TKP releases relay A1-CH energizes and remains energized during the release period. Relay A-GSN is re-energized via a f.c. of relay A1-CH and the points and signal stick relays 1W and 2-3D are switched to their left positions via circuits through f.c. 149 of relay 1WR and f.c. 153 of relay 2-3RD respectively, and store the required points and signal settings, i.e. points normal and signal cleared for westbound movement, to allow the westbound train to proceed. With the pick-up of relay A-GSN relay W-CH is energized and initiates the transmission of a second code message to the west end of siding A, resulting in the execution of the points and signal requirements stored in relays 1W and 2-3D. In a similar manner and when the westbound train has passed over the east end track circuit, the arrangement associated with the east end of the siding sets the points to reverse and the signal to clear eastbound to allow the eastbound train to leave the siding and proceed.