Patent GB-190906289-A (GB)
Title: Improvements in Automatic Electric Block Signal Systems.
Inventor: PRICE HAROLD WILBERFORCE
IPC: B61L13/04
Filed: 1909-03-16
Granted: 1909-10-21
Abstract: 6289. Price, H. W. March 16. Electrical systems, automatic. - In a signalling system for a single-track road on which the travelling may be in both directions, a danger signal is given on a train when passing a block junction when both of two contacts 19, 23 at that junction are closed. No safety signals are given. A train in passing through a block closes certain contacts at the two junctions next in the rear and the two junctions next ahead. When two trains approach within three blocks of one another, the contacts closed by the trains acting independently cause in combination the closing of both danger circuit contacts at all three intervening junctions. The system is also applied to a uni-direction track. At each block junction there are four relays 1, 2, 3, 4 with armatures 5, 6, 7, 8 respectively. The track relay 1 is energized by a battery 11 and is shortcircuited by a passing train. The relay 2 is energized by a battery 10 at the junction the next to the left through the contacts 22 on the armature 8, 20, on the armature 6 in parallel, and the contact 14 on the armature 5, all at the battery junction, and the contact 12 in the armature 5 at the relay junction. The relay 3 is energized by a battery 9 at the junction the next to the right through the contacts 21 on the armature 8, 13 on the armature 5 in series and the contact 17 on the armature 6 in parallel with the contacts 21, 13, all at the battery junction. The relay 4 is energized by a battery 9 at the junction the second to the right through contacts 21, 13, 17, as for the relay 3, at the battery junction and through the contact 16 on the armature 7 at the relay junction. Normally all the relays are energized. When a train enters a block, it short-circuits the relay 1 at the junction to the right of the block in which the train is and opens contacts 12, 13, 14. Openings of the contact 12 breaks the circuit of the relay 2 at the same junction. The armature 6 falls, contacts 17, 20 are opened, and contacts 18, 19 are closed. Opening of the contacts 17, 13 in the two branches of the circuit of the relay 3 in the junction the next to the left and of the relay 4 in the junction the second.to the left causes the armatures 7, 8 of those relays to fall. The falling of the armature 7 in the junction the next to left opens contact 16 and causes the armature 8 of the relay 4 in the same junction to fall. Further, the opening of the contact 14 on the armature 1 de energizes the relay 2 at the junction the next to the right. The whole result being : in the first junction to the right, relays 1, 2 are down, in the second to the right, relay 2 is down, in the first junction to the left, relays 3, 4 are down, and in the second junction to the left, relay 4 is down. This is the condition produced by one train acting alone, i.e. with the track clear. When two trains enter blocks separated by three junctions only, at the middle junction, the relay 2 fal's by one train and the relay 4 by the other. The contacts, on the armatures of these relays interact with the following results: opening of the contact 17 on the armature 6 and opening of the contact 21 on the armature 8, both of the middle junction, break the circuit of the relay 3 at the junction the next to the left, and its armature 6 falls acd, by opening the contact 16, causes the fall of the armature 8 at the same junction ; opening of the contact 20 on the armature 6 and opening of the contact 22 on the armature 8, both at the middle junction, break the circuit of the relay 2 at the junction the next to the right, inter-alia, opening the contact 17 on the armature 6 of that relay which together with contact 21 at the same junction (that to the right of the middle junction) breaks the circuit of the relay 3 at the middle junction. Now the armatures 2, 4 at each of the three junctions between the two trains are down, and thereby, at each junction the contacts 19, 23 are closed, thus providing the danger signal circuits. Either train proceeding across one of the three intervening junctions will complete a circuit from a battery 10 through contacts 23, 19, wire 40, rail W, driving-wheels and frame of engine, the signal-receiving apparatus on the engine, insulated front truck, rail Y, back to battery 10. On each side of the junction railinsulations, an insulated rail is provided, W on one side, and X on the other. These rails prevent a train from shortcircuiting two adjacent track relays at the same time until the signal-receiving wheels have passed the junction. The rail W is connected to the rail U when the contact 18 on the armature 6 is closed, and the rail X to the rail Z when the contact 15 on the armature 7 is closed. Normally both are open. When a train passes from one block to the next to the right, the armature 6 at the junction to be crossed is down, the contact 18 is closed and the rail W forms electrically a continuation of the rail U so that the train passes from the rail U to the junction without any alteration of the positions of the contacts. Also the relay 3 of the junction is energized as normally, and the contact 15 is open, so providing a break in the line of rail Z. When a train passes in the opposite direction, the contact 15 is closed and the contact 18 is open. If desired, to increase the current through the relay 1, a relay C may be placed in the circuit of the relay 1. As shown, the rail Z is broken by an insulation, the common terminal of the relay is connected to the unbroken rail, and the other two to their proper rails at the sides of the insulation. Fig. 2 shows a modified arrangement for uni-direction track working. The direction of working is from right to left. A train in a block short-circuits the track relay 1<1> of the junction behind it and causes its armature to fall, which in turn causes the armatures of the relay 2<1> in the same junction and the relay 2<1> in the second junction to the rear to fall. These close contacts 19<1> and ensure that a train passing either junction will receive a signal from the battery 10<1> by completing the circuit from the rail Y<1>, to the battery 10<1>, contact 19<1>, and wire 40<1> through the signal-receiving apparatus on the engine. Insulated rail lengths W<1> are provided in one rail line of each junction.