Patent GB-1465504-A (GB)
Title: Freight car marshalling system for a level marshalling yard
IPC: B61G7/04
Filed: 1974-04-19
Abstract: 1465504 Railway marshalling system; retarder control system JAPANESE NATIONAL RAILWAYS and KAYABAKOGYO KK 19 April 1974 [25 April 1973] 17383/74 Headings B7L and B7N A freight car classification system for a level marshalling yard having a receiving track and a plurality of classification tracks branching therefrom through switches comprises an automatic decoupling unit installed along the receiving track for disconnecting the freight cars from each other, track propulsion units installed along the receiving and classification tracks for moving the freight cars, three groups of accelerator-retarder devices along the receiving and classification tracks for separating and maintaining movement of the freight cars at predetermined speeds, and a control unit for automatically controlling operation of the decoupling unit, track propulsion units and switches. The track propulsion unit 33 consists of a trolley 33, Fig. 3, running on guides 50 between railway tracks 46. The trolley is guided laterally by rollers 32 and moved along the track by an hydraulic motor driving pinions 40 engaging racks 51. The trolley supports two units 45 movable longitudinally of the trolley and normally biased towards each other. Each unit 45 includes two hydraulically extensible arms 54 carrying rollers 55. In operation the arms 54 of the two units are extended whereby the two units grip a pair of carriage wheels firmly between the units. Each accelerator-retarder device 70a, Fig. 4, comprises a cylinder 71 supported by a track rail 46, and a plunger 72. The plunger supports an hydraulic telescopic tappet 81 carrying a pressure-sensitive valve 78, a sliding valve 74 being mounted on the inner end of the plunger. The cylinder has a port 77 connected to a high pressure line and a port 80 connected to a low pressure or return line. When a freight car passes over the device at a speed exceeding a predetermined speed, pressure-sensitive valve 78 is closed and the working fluid is forced to flow through valve 75 to high-pressure port 77 so that a retarding force is exerted against the car wheel. As the wheel passes away from the plunger, the pressure drops and valve 78 opens whereby the plunger is extended by the low pressure source without applying any accelerating force to the wheel. When a freight car passes over the device at a speed below the predetermined speed, pressure-sensitive valve 78 remains open so that the working fluid flows to low-pressure port 80 and no retarding force is applied to the car wheel during the down stroke. At the end of the down stroke, hydraulic tappet 81 is actuated so as to move sliding valve 74 and connect chamber 73 with the high-pressure line, whereby plunger 72 is extended under high-pressure so as to apply an accelerating force to the wheel. The decoupling unit 100 is mounted on a member 109 having an extension 112 pivoted at 113. Operation of hydraulic jack 114 tilts the decoupling unit laterally to an operative position between two freight cars as shown in chain lines (Fig. 5). The decoupling mechanism 103 is pivotally supported by an arm 110 mounted on parallel linkage 102 whereby the mechanism may be correctly positioned longitudinally of the track 46 (Fig. 8, not shown). The decoupling mechanism comprises a frame 140 supporting depending arms 141, 142. Lifting fingers 144, 145 operated by hydraulic means 150 are slidable along the arm 141. The arm 142 is pivotally connected at 162 to a support plate 163 running on rollers 164 along the frame 140 under the control of hydraulic cylinder 171. A further hydraulic cylinder 167 connected between the support plate 163 and arm 142 rocks the fingers 147, 148 relative to the support plate.