GB262469A - Railway train control systems - Google Patents

Abstract

262,469. Continuous Train Control Corporation, (Assignees of Clark, T. E., and Clark, J. E.). Dec. 5, 1925, [Convention date]. Fluid-pressure.-In an automatic braking system for railway vehicles in which highfrequency current is supplied to insulated track rail sections under predetermined conditions and is adapted to act inductively on train carried apparatus to apply the brakes, brake application is controlled by a normally-energized electromagnetic valve mechanism 118. The circuit of magnet 118 includes " forestalling " and " resetting " contacts, not shown, and pneumatically operated contacts 117. Fig. 12 shows the general arrangements of valves, which are described in detail. An inlet valve 405 and exhaust valve 409 are normally respectively held open and closed when device 118 is energized. Air is thus supplied to the underside of a piston maintaining contact 117 closed, to a reservoir 422, to the underside of a piston 423 maintaining open a valve 428 interposed between pipe 434 leading to the usual engineer's valve, not shown, and brake-pipe 435, and to one side of a piston operating a slide-valve 431. When device 118 is de-energized, the above mentioned air supply exhausts slowly through valve 409 and sounds a warning whistle 420, time being allowed for depression of the forestalling " key before contacts 117 open. Valve 428 seats, preventing recharging. of the brake-pipe but allowing further reduction of pressure by the engineer's valve. A by-pass 437 around valve 428 is normally held closed and sealed, and a cock 439 is provided for blocking the engineer's valve when the locomotive is coupled in a train handled by another locomotive. Brake-pipe 435 is connected through a strainer 441 and pipe 442 to the upper side of slide 431 and through a post 443 to the under side of a piston 445 which normally seats a valve 446 owing to an equal pressure being supplied to the upper side of the piston through the slide 431. The space above piston 445 is connected through a port 449 to a reduction reservoir 451 and to the under side of a diaphragm 460 carrying a needle valve 453, and through the normally open valve 453 to a port 455 below slide 431. The space above a diaphragm 459 is connected to a holding reservoir 457 and to a port 458. When exhaust occurs through whistle 420, slide 431 is moved to the right, cutting off supply to space above piston 445, and connecting port 455 to a restricted vent 461. Reservoir 451, space above piston 445, and space under diaphragm 460 exhaust until valve 453 closes, retaining remaining pressure in reservoir 451. Valve 446 is unseated, and the brakepipe 435 is vented until the pressures above and below piston 445 are equalized, the action of piston 445 being similar to the function of the usual equalizing valve of automatic air-brake systems.