Patent GB-348512-A (GB)
Title: Improvements in and relating to electrical signalling systems for railways
IPC: B61L29/22
Filed: 1930-01-06
Abstract: 348,512. Automatic electric signalling system for railways. MATTEI, S. and YZETTA, E. N., 682, BartolomÚ Mitre, Buenos Aires. Jan. 6, 1930, No. 511. [Class 105.] Relates to an automatic electrical system of train control and cab and track signalling in which a train-carried source of current feeds a track conductor having resistances inserted therein and extending the length of a block section, track signalling means being connected between the conductor and the track rails so that the track signals in the vicinity of the train are actuated with an intensity depending on the proximity of the train. According to the invention the part of the circuit on the train, shown in Figs. 3E and 3F, includes an underload relay EI whereby lamp and audible signals are given when the track conductor is interrupted, for instance, by the opening of a manual or crossing-gate controlled switch, or when a second train is in proximity and so causes a reduction in the current from each source. In the arrangement shown in Fig. 4A an additional relay JJ is actuated whereby brake application and power cut-off are effected by means of servo motors AT. When a train is stationary a centrifugalgovernor-actuated switch U cause the source of current G to be cut off from the track conductor CCL but connects a relay AA thereto which if energized by current from a second train re-inserts the source G of the first train and so signals are given on both trains bv the action of the underload relays EI as above described. The driver may annul the train control and the audible signal by opening a switch AR or AP but the danger lamp signal LR remains. A pilot lamp LB indicates that the source is working. The track signals include audible signals with a series resistance so that they are not energized until the train is comparatively close whereas the track lamp signals are energized earlier. Points and crossing lines may be protected by inserting in the conductor line a switch which is electromagnetically opened when a conflicting second train earths an insulated rail section, or a semaphore or lamp signal for the crossing line may be actuated in the manner of the track signals. For instance, as shown in Fig. 5B a train on the main line BI will energize with increasing intensity a semaphore signal BK on the branch line BJ; but should a train on the branch line reach the junction first then, by means of an insulated rail section BM and current from a train on the main line B1, a switch BN is operated to open the track conductor CCL so that the main line train receives a warning signal. When the branch train reaches a rail section BO the switch BN is operated to close the track conductor CCL and the main-line train can then proceed. A detector contact arm BQ opens the track conductor CCL unless the points are set for the main line. Fig. 4B shows a level crossing lamp signal having mirrors BA, BB, BC, BD, BE for directing light on to the diaphragms VC which are provided with a transparent arrow. Shades BG, BF are fitted. The level crossing gates may be opened immediately after the passage of a train if a delay action is provided to prevent the opening of the track conductor switch I<1> operated by the gate. Fig. 3B shows a magnet BT energized from the track conductor CCL and so holding the arm of switch I<1> until the train is out of range. The switch arm is lifted by the traction cable of the gate when the latter is closed. The signalling current may be provided by a turbo-generator or be taken from the lighting circuit, or on electric railways the power current may be used with a resistance or motor generator to reduce the voltage.