GB1280626A - Controlling system for means for adjusting speeds of freight cars in a yard - Google Patents

Abstract

1280626 Adjusting freight-car speeds by mobile retarder HITACHI Ltd and JAPANESE NATIONAL RAILWAYS 5 March 1970 [10 March 1969] 10724/70 Heading F2E Between the rails of each of a number of sorting tracks 14a, &c., Fig. 1, in a marshalling yard, is located a mobile retarder e.g. 18a consisting of a driving device 26, Fig. 2a, and a pushing or engaging device 28, on wheels 30 to 32<SP>1</SP> and 42 to 44<SP>1</SP> respectively, running between rails 24, 24<SP>1</SP>. The driving device in turn consists of a driving motor unit, preferably a linear induction motor, and a control unit. Part of the control unit consists of detectors 38, 40, to detect the wheels of a freight car. The output from detector 38 passes in part to an arm controller 60 (see below) and partly to a timer 62, the output from which is fed to a controller 64 which controls the retarder motor; the output from detector 40 is fed to the controller 64. In operation, the retarder is initially at rest. When a freight car proceeds into the sorting track, detector 38 detects one of its first wheels, whereupon timer 62 is started, and arm controller 60 is actuated. In consequence two arms carrying rollers 48, 48<SP>1</SP>, Fig. 2b, are hydraulically extended into the paths of the two wheels on the leading axle. When one of the first wheels reaches detector 40, controller 60 is actuated whereby the retarder starts and accelerates at a predetermined value of acceleration. The duration of acceleration is equal to the predetermined time limit T of the timer 62 diminished by the time taken for the car wheel to travel from detector 38 to detector 40. Thus, the greater the speed of the freight car, the greater the duration of acceleration. At the end of time T, the output from the timer to controller 64 provides an instruction for the retarder to begin coasting or braking. The freight car advances relatively to the retarder until the first wheels reach the rollers 48, 48<SP>1</SP>; thereupon further rollers 46, 461, on arms 50, 50<SP>1</SP> respectively, Figs. 2a, 2c, are extended behind these first wheels so the wheels are held. Next, the retarder is further decelerated to a predetermined speed, e.g. 5 km./h., and thereafter drives positively to "inch" the freight car to the location where it is to be released from the retarder; at this place the rollers 46 &c. are retracted and the retarder is quickly braked, optionally by reversing the phase rotation of the 3-phase voltage supplied to its linear induction motor. Finally the retarder moves backwards at full speed to a position where it awaits the arrival of the next freight car. Two or more coupled frieght cars may be dealt with during a single cycle of operation by a retarder.