Patent GB-190429008-A (GB)
Title: Improvements in Railway Block-signalling.
Inventor: SYKES WILLIAM ROBERT
Filed: 1904-12-30
Granted: 1905-12-30
Abstract: 29,008. Sykes, W. R. Dec. 30. Signalling - systems ; controlling and locking signals; interlocking; hand-levers ; crossing-gate signals.-Relates to electrically-controlled block signalling-systems in which the operator in the 'home' cabin is enabled to control the starting- signal for a train at the opposite end of the section. The invention is described with reference to a single-track section on which trains are to be worked in opposite directions, but it is not exclusively applicable to such systems. Figs. 1 and 3 show the apparatus at the two ends A, B of the single-track section. The block indicators a, b are combined with the block bells, and are provided with slides which are operated by the hand-slides A', B' and are visible through the dial openings. These slides, like the hand-slides, are capable of occupying three positions. When the hand-slide is in its normal or intermediate position, as shown in Figs. 1 and 3, the block indicator reads line blocked.' When the handslide is pulled forwards, the indication is 'train ' to ;' and when it is pushed inwards the indication is 'train from.' Locking-devices A<2>, B' co-operate with the tappet rods of the point-operating levers to lock the points in the position corresponding to that of the hand-slide when set in either of its extreme positions. The hand-slides A', B<1> when in their normal or mid-position are locked by detents A<3>, B<3> against forward movement, but are both capable of being pushed in, that being the first step in preparing to accept a train at either end of the section. The same detent serves to lock the hand-slide in either of its extreme positions. The method of operation is as follows :-Assuming that it is desired to despatch a train from A to B, the operator at A presses his bell plunger A<12>, thereby sending a current from the battery A<25> through the line-wire X, block bell b, and coil B<15> of a non-sticking polarized relay, of which the tongue B<28> normally breaks both the controlled circuits. The operator at B, in response to the bell signal, sets the road and then pushes in the slide B', the points being thereby locked in the correct position and the switch arm B<22> caused to bridge the contacts B<16>, B<18>. The effect of this is to connect the battery B<43> on the one hand to earth through the electromagnet B<40> of the home signal BH, and on the other hand to the line-wire Y through switch B<22>, wire B<41>, and the contactsprings of two switches B", B<10> which normally play no part in the sequence of operations. The circuit of the battery B<43> is as yet incomplete, being broken at the contact-spring A<16> of the switch A<22>. The operator at B then presses his bell plunger B", sending a current from the battery B<29> (the contact-spring B<23> being raised) through the line-wire X, indicator a, and relay A<15> to earth. Contact is made at A<30>, and current flows from the battery A<29> through the coils of the semaphore indicator A<19> and through the switch A<5> to the electromagnet A<4> which controls the detent A<3>. While this current is still flowing and the slide A<1> is free, the operator at A pulls out the slide, thereby completing the circuit of the battery B" through the line-wire Y, contacts A<16>, A<17>, and the electromagnet A<39> of the starting-signal AS. The starting-signal AS and home signal BH are thus lowered simultaneously, and the train admitted to the section. The points at A are at the same time locked by the device A'. The train, as it enters the section, depresses a treadle switch A<45> and energizes the " sticking" relay A<36> so as to swing over the tongue A<37> against the contact A<38>, and thus short-circuit the electromagnet of the starting-signal AS, which immediately returns to 'danger.' The shortcircuit persists while the train is in the section, but the home signal B<40> remains in the line ' clear ' position. Before the train actually enters the section, it is possible for either operator to return the starting-signal AS to 'danger.' The operator at A can do so by means of the switch A<53>, which short-circuits the electromagnet controlling the signal. The operator at B can effect the same result by shifting the switch arm B<42> to the dead contact B<54>, thereby breaking the line circuit and setting both home and starting signals at 'danger.' If the switch arm B<42> is moved on to the contact B", the home signal BH returns to danger,' while the starting-signal AS remains at line clear.' When the train arrives at B, it depresses the treadle B<45>, closing the circuit of the electromagnet B<4> through the wire B<46> and switch B<5>. The operator at B then returns the slide B' to the normal position. Having done this, he depresses his bell plunger B", sending current from the battery B<25> through the line-wire X, block bell a, and relay A<15>. This current is of opposite sign to that sent in acceptance of the train, and it effects the opposite movement of the relay tongue A<28>, which then makes contact at A<31>, thereby closing the circuit of the battery A<29> through the switch A<5> and electromagnet A'. The operator at A restores the slide A' to the normal position, and in so doing closes momentarily a branch circuit through the relay A<36> so as to return the tongue A<37> to its normal position in contact with the stop A<35>. The whole apparatus is then in its normal state. The switches A<10>, All and B<10>, B<11> are provided for the purpose of enabling the operator who has accepted a train to unlock the slide which he bas pushed in, and thereby enable the slide at the other box to be released. By this means, an acceptance of a train can be cancelled if it has not entered the section. Assuming that the slide at A has been pulled out and that at B pushed in, it is possible on a prearranged signal for the plungers A<82>, B<85> to be depressed simultaneously. Current then flows from the battery A<34> through the line-wire Y to the relay B<20,> returning through earth to the tongue of the relay A<36>. The contact made at B<55> closes the circuit of the battery B<29> through the electromagnet B', thus releasing the slide B<1>. When a level crossing occurs between the stations, a branch to earth from the line Y is used to give a visual signal in the gate-keeper's hut, and, through a relay, to give a bell signal, the bell ringing until a switch is opened by the gate-keeper. This switch closes automatically when the current in the line Y ceases. The gates operate switches which give 'line-clear' signals on both sides while the gates are closed and the track is clear.