Patent GB-190317851-A (GB)
Title: Improvements in or relating to Electric Railways.
Inventor: WESTINGHOUSE GEORGE
Filed: 1903-08-18
Granted: 1904-08-18
Abstract: 17,851. Westinghouse, G. Aug. 18. Electric railways, signalling on.-Relates particularly to tube or simitar railways and consists in providing circuit-breakers at certain intervals to enable any length of the tunnel to be electrically isolated should a short-circuit occur. This arrangement may be connected with the signalling-devices, e g. with the controlling-circuit of an electropneumatic system so that some or all the signals may be set to danger when the circuit-breakers are opened. The circuit-breakers may be of any suitable type and may be arranged to control the current supply to an entire block or signalling section or spaced at intervals of one train length. They may be actuated by power and controlled by magnetic or other means, and are preferably furnished with means by which they can be re-set from a distant point. Fig. 3 is a diagrammatic view showing circuit-breakers operated by fluid pressure under electromagnetic control from the signalling-cabin or substation. The circuit-breaker is operated by a piston 10 in a cylinder 11 to which fluid under pressure is admitted from a main pipe 12, branch 13, and controlling-valve 14, 15 operated by the electromagnet 16. When the magnet is de-energized, the valve 15 is opened to exhaust, and the circuit-breaker is opened by the action of the spring 24. The electromagnets 16 are included in the governing-circuit 20, 21 containing the battery 19. An overhead coil 23 in the main circuit is connected to a switch 22 in the electromagnet circuit to cause the circuitbreaker to be opened when the current in the main circuit is excessive. The main pipe 12 is fed from a reservoir 25 and is fitted with cocks 27 to enable the circuit-breakers to be opened. To enable the circuit-breakers to be closed only from the controlling-station, a switch 29 is arranged in the governing-circuit and attached to the circuit-breaker so that it is opened when the circuit-breaker is opened and a branch lead 30 is connected to a third conductor 31 in connection with the negative side of the battery 19 through an indicating-device 32, around which is arranged a switch shunt 33. The governing-circuit can be re-made by closing the switch 33. When more than one circuit-breaker is provided in a section, they may be opened independently by arranging the electromagnets in parallel and providing switches 34 in the governing-circuits ; the conductors of the magnets are brought back to the controlling-station as shown in the dotted lines at 35, a lamp 36 or other indicating-device being inserted in each circuit and the lead 20 dispensed with. A special alarm or indicator circuit may be provided, switches being arranged in the electromagnet - controlling circuit, which, when opened, close the alarm or indicator circuit. The magnets may be arranged in series or parallel. The circuit-breakers may be operated by fluidpressure apparatus similar to that employed for operating brakes. Two forms of fluid-pressure apparatus are described in detail ; a continuous pipe and branches supply the fluid pressure, and a triple valve and auxiliary reservoir are provided for controlling the pressure in the cylinder of the circuit-breaker. The triple valve consists of a slide valve operated by a controlling-piston subject on one side to the fluid pressure in the main and on the other to the pressure in the auxiliary reservoir. The main pipe may be fitted with exhaust cocks and also with an exhaust valve operated by an overload coil. A device operated by the reduction of pressure in the main pipe is provided to give warning in the signal cabin &c. when a circuit-breaker has been opened locally. This device consists of a piston moving in a cylinder providad with valve arrangements which cause the piston to move when there is a reduction of pressure in the main pipe and thus uncover the aperture of a whistle &c. To enable any one circuit-breaker to be opened, when more than one circuit-breaker is provided in each block, a separate indicator pipe is connected at one and to the alarm cylinder and by branch pipes to the triple valves, which branch pipes may be opened to the atmosphere. The circuit-breaker can only be again closed by the signalmen by means of a three-way cock which equalizes the pressure on the two sides of the piston in the alarm cylinder. A vacuum system may be used in place of a pressure system, or a system entirely controlled and operated by electric means may be employed.