Abstract: A retarder, suitable when mounted in association with a rail of a railway track for reducing the speed of a wagon rolling along the track, includes an hydraulic unit which comprises a hollow member, a piston slidably housed in that member, and a piston rod. A portion of the hydraulic unit is, for retardation of the wagon, disposed in the path of a wagon wheel. When that portion is engaged, directly or indirectly, by a wheel it is deflected by, and out of the path of, the wheel to permit the wheel to pass the retarder. The ratio of the diameter of the piston to the diameter of the piston rod is in the range 2.80:1 to 6.00:1 and the ratio of the diameter of the piston to the length of stroke of the hydraulic unit is in the range 0.53:1 to 1.20:1.

Abstract: A retarder, suitable for mounting with respect to a rail of a railway track for reducing the speed of a wagon rolling along the track, includes an hydraulic unit a portion of which, for retardation of the wagon, is disposed in the path of a wheel of the wagon. That portion when engaged, directly or indirectly, by the wheel is deflected by, and out of the path of, the wheel. A thruster device, disposed alongside the unit and capable also of deflecting the portion out of the path, includes a displaceable element which is normally disengaged from the portion but which upon initial movement thereof is so tilted that a part thereof comes into driving engagement with the portion. On continued movement of the element the driving engagement is maintained and the portion moves from its position in the path of the wheel into another position out of the path.

Abstract: A retarder, suitable for reducing the speed of a wagon rolling along a railway track, includes a retainer, which is adapted to be secured upon or adjacent a rail of the track, and an hydraulic unit which is fitted in the retainer. A portion of the unit normally projects from the retainer thus to lie in the path of a wheel of the wagon so as to be engageable by that wheel. The portion is movable inwardly of the retainer to a position, out of the path, in which it permits the wheel to pass the retarder. The retarder includes holding mechanism for maintaining the portion in that position.

Abstract: A buffer stop comprising an arm capable of being pivotally-mounted at or near one end portion on or adjacent a railway track, and a piston-and-cylinder device. One end portion of the piston-and-cylinder device is pivotally-connectible at or near the other end portion of the arm. The other end portion of the device is capable of being pivotally-mounted on or adjacent the railway track at a distance away from the one end portion of the arm.

Abstract: A power transfer unit for transferring power between two separate hydraulic circuits comprising a casing, a pair of cylinder blocks in the casing, cylinders within each cylinder block, a piston in each cylinder, a leakage chamber within the casing, cam means located in said chamber for causing joint reciprocation of the pistons, pistons or extensions thereof extending from the cylinders to the cam means in the chamber, first valve means co-operating with the cylinders of the first block, second valve means co-operating with the cylinders of the second block, first leakage collecting means for the first valve means separate from said chamber, second leakage collecting means for the second valve means separate from said chamber, and a vent for said chamber separate from said leakage collecting means.By this arrangement any leakage to the chamber may be from either or both circuits and by virtue of the vent may be disposed of rather than fed back to either circuit.