GB756499A - Improvements relating to speed control systems for gravity operated railway marshalling yards - Google Patents

Abstract

756,499. Railway marshalling yards. METROPOLITAN - VICKERS - GES., Ltd., April 14, 1955 [May 4, 1954], No. 12973/54. Class 103 (1). In a brake control system for a railway marshalling yard a device Q, which continuously responds to the speed of a wagon in passing through a certain distance in a gravity sorting yard, gives a signal which operates a speed indicator S. The speed signal is passed to a converter C the output from which is made to vary with the square of the speed and is therefore a measure of the energy level of the moving wagons. The output from converter C is applied to the followers S1 and S2 which drive sliders S1 and S2 of variably tapped transformers U1 and U2. The connection to the follower F1 includes a back contact R1 operated by a relay coil R energized by closure of a track switch T1 until a normally closed track contact T2 is opened. Thus slider S 1 is adjusted to a position corresponding to the wagon energy level at T1. The position of slider S2 continuously represents the energy level of the wagon throughout the working distance. Thus the output E2 from transformer U2 and output E3 are increased by the amplifier AMP from the output voltage of transformer U1 or modified by a device TD which determines the distance to a wagon already in the siding, are used to energize coils W2 and W3 of an electromagnetic retarder control RC so that the position of an armature A is varied so that one or the other of relays O, L, M or H is energized to bring into action zero, light, medium, or high braking effect on the wagon. In another control circuit described, the output from the indicator S is passed to a rectifier and this is connected via variable resistors to the grids of two thermionic valves, one such connection being subject to closure by a switch moved by a wagon passing a predetermined point in the track. The amplified outputs from the valves are applied to two windings on a magnetic core so as to produce in a third winding a current or voltage representing the difference in the first two windings, and the output from the third winding is used to control relays such as O, L, M or H.