Patent GB-191421406-A (GB)
Title: Improvements in or relating to Control Systems for Railways and the like.
Inventor: COWELL JAMES
IPC: B61L3/10
Filed: 1914-10-22
Granted: 1915-10-22
Abstract: 21,406. Cowell, J., and McCaughan, T. Jan. 27, [Convention date]. Electrical s y s t e m s , non - automatic; track apparatus actuating signals on trains, and for stopping trains; indicating condition of bridges and the like. - Relates to a traffic - controlling system in which the brakes are automatically applied when the position and speed of the train together constitute a danger, by means comprising a speedometer device on the train and electric track ramps controlled by the signals. Referring to Fig. 1, the valve A<15> between the train-pipe A<5> and the vent A<16> has a piston-head A<13> which is either subject to pressure from the pipe A' (and supply B), or open to atmosphere at A<10>, according to the position of the ports D<3>, D<4> in the rod of a piston C working in a cylinder A<1>. The hooked extension D of the piston C is normally locked by a catch F, which is raised when the magnet F<2> is energized by a 'danger' current picked up by the brush &c. G. A valve W which controls the admission of fluid from the pipe A<7> to the cylinder A', or the opening of the cylinder to atmosphere at W<3>, is controlled by a cam W<8> operated by the speedometer. With a ' danger ' speed, the valve W falls and closes a switch E, E in the circuit of the magnet F<2>, which becomes energized, to free the piston C, if the brush G contacts with an energized ramp. The piston C then moves to the left, and the piston A<13> being open to atmosphere is raised by the pressure in the train-pipe A<5>, which is thus vented, and the brakes applied. When the speed again falls below the predetermined limit, the valve W is raised to open the cylinder A' to atmosphere, and the piston C is returned by a spring D<5>. Fig. 2 shows a set of connexions for a track section of a double line, the arrow a indicating the direction of traffic on the set of rails shown. The rails are insulated from one another, and one rail has an insulated section L-M, J, K being respectively the ' home' and ' starting ' signals (or levers) and P the (main) battery supplying the ramps N, O. In operation, with a train moving above the predetermined speed, the brake-operating circuits are made as follows: (1) When the train is approaching section L-M with signals J at ' danger ' (section L-M clear), the circuit comprises ramp N, battery P, contacts J<2>, J', rail at L<4>, and through train, to ramp. (2) When the train is leaving section L-M with signal K at ' danger ' the circuit comprises ramp O, contacts K<4>, K<3>, battery P, contacts K<1>, K<2>, rail at M<4>, and through train to ramp. (3) When the train is approaching section L-M with obstructing occupant in L-M (irrespective of position of signal J), the circuit comprises ramp N, battery P, rail at c, across occupant, and through train, to ramp. Auxiliary ramps Q, R may be provided (out of line with the ramps N, O) to actuate warning-signals on the train. An emergency battery P<1> may also be provided and is automatically switched into the ramp circuits on failure of the main battery P. The battery P' is normally cut out at S, but this contact is closed by the dropping of the armature T<1> of the magnet V when the main battery fails. At the same time, a bell circuit from the battery P<3> is closed at T<5> to ring a warning- bell U in the signal cabin. As applied to a single line for traffic in both directions, at each end of the section L-M are additional short insulated sections with connexions to relay circuits which includes switches on the starting- signals at each end of the section. In addition to this arrangement, where the section includes a loop &c., both rails of the loop and main line have insulated sections, and the brake-operating circuits include contacts on the points levers. In the case of a bridge &c., to stop an approaching train if any part of the line is broken, both metals of the track for the whole span. of the bridge &c. form an insulated section in a normally closed circuit operating a relay which controls the brake-operating circuits at each end of the insulated sections.