Patent GB-256642-A (GB)
Title: Improvements relating to railway signalling
IPC: B61L23/22
Filed: 1926-08-06
Abstract: 256,642. General Railway Signal Co., (Assignees of Wight, S. N.). Aug. 6, 1925, [Convention date]. Electrical systems, non-automatic.-With an automatic system of signalling for single or double tracks, of known types, of which an example is described in Specification 11804/14, there is combined means for manual control of a considerable length of track from a central cabin and for indicating signal, point and train movements in the cabin. The manual control provides the equivalent of a train order system, but all orders are indicated by track signals. Each control cabin is connecte I by an independent, line wire to apparatus at each switch-point; this circuit includes a polarized control relay at the points and indicator relay in the cabin which are energized either from a battery at the cabin or one at the points according to the existing conditions of the track and of the traffic. The application of the system to several types of automatic system is described in the Specification. Fig. 3 shows a lay-out of apparatus at the points at one end of a siding F between two single line sections N, O of track together with the control apparatus CF<e> in the cabin 10 to which is connected by the line wire 39. Fig. 1 shows the general lay out of the track, three sidings D, E, F being arranged to be controlled from the cabin 10. Traffic is controlled by a series of automatic signals in each section, shown in the figures on the right of the track. These signals are, controlled by the track relays suitably spaced, and line relays H<1>, H<2>, H<7> controlled thereby so as to permit control of a series of signals by a passing train. For the manual control, there is provided a control relay ZF<e>, Fig. 3, and a stick relay SR<2> together with extra contacts on the track and home relays. A separate line wire 39 and a common return C connect each control apparatus CD<w>, CF<e> to the corresponding apparatus at the points. In the system shown in Fig. 3, the points are manually operated by the traindriver according to the indication given by the " take-siding " signal S, which is controlled by the relay ZFe. The blockoperator may maintain any signal at danger and can select which signals to clear, but cannot clear signals if traffic conditions are unfavourable. The location of traffic and their movements are indicated to him by single-stroke bells 79 of different tone for each set of points; indications on any bell are distinguished by the time intervals between the two strokes, or between two pairs of strokes or by a series of strokes. The bells are controlled by a relay 38 in the line wire 39 and the circuit is controlled by relays at the points or signals and by contacts on the signal arms. In a modification the bell relay is energized bv impulses of current induced in a transformer by the making and breaking of the line circuit. As shown in Fig. 3, the bell is struck once at each make and break of the line circuit bv means of the back and front contacts of the relay armature 81. Modifications involving "takesiding " signals which are exposed and those which are hidden when the operating electromagnet is energized are described. The various steps in passing traffic along the track under various conditions such as trains following one another, trains meeting and passing at a selected siding, a fast train following and passing ahead of a slow train in a siding are described in detail. The following United States Specifications are referred to :-1,092,266 which describes an electric contact maker which is operable by movement of a semaphore in one direction only, and 1,476,866 which describes means for preventing throwing a switch in front of a fast-moving train. The Specification as open to inspection under Sect. 91 (3) (a) comprises also a modification in which the points are operated by an electrically operated switch-machine, such as that described in United States Specification 1,466,903, which is controlled by contacts on the relay LF<e> and by contacts on track relays and track signals. The operation of the machine is indicated to the block operator by strokes of the bell 79. This subjectmatter does not appear in the Specification as accepted.