Patent GB-526751-A (GB)
Title: Improvements relating to railway traffic controlling apparatus
IPC: B61L7/08
Filed: 1939-03-10
Abstract: 526,751. Railway traffic control system. WESTINGHOUSE BRAKE & SIGNAL CO., Ltd., PETER, L. H. and SHIPP, D. G. March 10, 1939, No. 7832. [Class 105] In a railway traffic control system of the kind in which the selective operation of trafficcontrolling devices such as points and signals is effected by code impulses sent over live wires from a central control point means are provided for transferring control from the centre to a local or field station by transmission to the selected station of a special code impulse, the central control being cut off when the local control is operative. Preferably, local control is established only when the traffic control devices concerned are in normal position, and by a local king-lever or switch operated after receipt of the special code. The invention is described as applied to a system of the kind described in Specification 399,539, using code elements X, Y, Z, as described therein. Fig. 1 is a diagram of a field station comprising main line track sections DT, ET, FT and a loop line with track section CT leading to or from the main line through a track switch operated by a point machine W. Signals RA, RB control left to right traffic, and signals LA, LB right to left. Relay and other apparatus for both remote and local control of the station are housed in cabin CB. Figs. 2, 3 are respectively diagrams of portions of storage units FSU1, FSU2 of the kind described in the Specification referred to, adapted for use with the present invention. Code elements X, Y, Z from the control centre operate relays 6XS, 6YS of unit FSU1 to operate the point relay WR controlling point machine W, and also operate relays 7XS, 7YS, of this unit to control signal relays LHS, RHS. These relay circuits over wires 26-29 leading from the field coding unit are controlled by contacts of a delivery relay D. A change-over relay QR, Fig. 3 is set to normal or reverse position by energizing its coils N, R. respectively, both circuits including a series of point and signal indication relay contacts to ensure usual safety condition. In normal position, contacts QR (N) are closed in the wires 26-29 leading from the field coding unit, in wires 56, 57, Fig. 2, leading to point relay WR, and in wires 58, 59 leading to signal relays LHS, RHS. A point control lever P, Fig. 2, for local control, has contacts P (N) P (R) closed respectively when the lever is in normal and reverse positions. A local signal control lever S has contact S (N) closed with the lever in central normal position, and contacts SR (R), SL (R) closed when the lever is moved to right and left respectively to energize relays LHS, RHS to clear signals RA, RB, or LA, LB the selection of the signal being automatic in accordance with the position of the track switch in known manner. A local hand-operated king- lever is-provided at K, Fig. 3 with an electric lock KL to retain the lever in reverse position for remote control and in normal position for local control. In its reverse position the lever also locks, mechanically or otherwise, the levers P, S so that these cannot be operated whilst remote control is effective. In this position the lever also closes contacts K (R) in the wires 28, 29 leading to delivery relay D, Fig. 3, to permit transmission of the special code signal to the appropriate relay, which, as described, is the relay 7YS Fig. 3. The energization of the change-over relay QR is controlled by relays XQR, YQR, Fig. 3, which in turn are controlled by the relays 7YS, 7XS. For central control working, relay 7YS is deenergized, and relay 7XS is energized from terminal B over wire 46, contacts B2, D1. C4, winding 7XS to terminal C. Under these circumstances relay YQR is de-energized and relay XQR energized from terminal B over wire 55, contacts A5, wire 58, back contact YQR2 of relay YQR, winding XQR to terminal C. Relay QR is therefore normally energized from terminal B, over a series of indication relay contacts, contact XQR1 of relay XQR, winding N of relay QR, to terminal C. The point relay WR and signal relays LHS, RHS can therefore be remotely controlled by code impulses as in Specification 399,539 as the wire circuits involved, viz. 56-59 and 26-29 are completed by the QR (N) contacts, Fig. 2. The king-lever, Fig. 3 is held locked as the release circuit is broken at contact QR (R). To effect transfer of control to the local field station, the special code signal is transmitted over closed K (R) contacts in wires 28, 29. Fig. 3, to relay D to effect energization of relay 7YS, relay 7XS being de-energized by breaking contact D1. Relay XQR is thus de-energized by breaking of front contact A5 of relay 7XS, and relay YQR is energized over wire 55, front contact A5 of relay 7YS, back contact B4, wire 59, back contact XQR2 of relay XQR, winding YQR to terminal C. Winding N of relay QR is de-energized by breaking of contact XQR1 and winding R is energized by closure of contact YQR1. Consequent closure of contact QR (R) closes circuit through a lamp KLL indicating that the special code signal has been received, and prepares a circuit through the release magnet at KL so that when the local operator initiates movement of lever K towards its normal position contact K (AE), which is temporarily closed as lever K moves from one position to another, completes the circuit of the lock release magnet and permits completion of lever K movement, which is again locked in the normal position. Breaking the various contacts QR (N), Fig. 2, prevents remote control of relays WR, LHS, RHS, but cancellation of the special code signal may be effected from the central control until lever K is moved to its normal position, so breaking contacts K (R) in the wires 28, 29, Fig. 3, thus cutting out remote control. Movement of lever K to normal position also unlocks levers P, S, Fig. 2, so that, as contacts QR (R) Fig. 2 are now closed, local control of relay WR may be effected by lever P and its contacts P (N), P (R), and local control of signal relays LHS, RHS may be effected by lever S with its contacts S (N), SR (R), SL (R). The circuits of relays LHS, RHS include front contact GSRI of a relay GSR energized when lever S is at normal and maintained energized until a train or vehicle enters track section ET and de-energizes a corresponding track relay to interrupt stick circuit of relay GSR at contact ETR1. Operations of relay QR and of lever K are indicated at the central point of control by code impulses sent over conductor 35, Fig. 3. After setting track switch and signals to normal, central control is re-established by moving lever K to reverse position, a code impulse being thereby sent to the central control point indicating the desire to re-establish central control, the central operator then sending the requisite code impulses to energize relay XQR, Fig. 3 and restore relay QR to normal. A code impulse is sent to the central point indicating that transfer to central control is completed. Release of approach locking of the track switch after an interval of time is effected by relay JR, Fig. 2, when central control is established, and by a slow, acting relay JRS controlled by a push-button switch JRB when local control is established. Occupation of track sections ET, FT and the setting of track switch and signals by code control from the central point are indicated at the local station by relay contact mechanism M. The specification also describes the application to a lay-out having main signals controlled from the central point only, and shunt signals under local control only, the track switch being controlled by code from the central point or locally by the local operator.