Retarders suitable for wagon speed control

A retarder, suitable when mounted upon or adjacent a rail of a railway track for reducing the speed of a wagon rolling along said track, comprising a hydraulic unit a portion of which, for retardation of said wagon, is disposed in the path of a wheel of said wagon, said portion when engaged, directly or indirectly, by a said wheel being deflected by, and out of the path of, said wheel to permit the wheel to pass the retarder, and thruster means, disposed alongside said unit and capable also of deflecting said portion out of said path, said thruster means having a displaceable element which is normally disengaged from said portion of said unit but which upon initial movement thereof, under a force applied thereto, is so tilted that a part thereof comes into driving engagement with said portion and on continued movement of said element said driving engagement is maintained and said portion is moved from its position in the path of said wheel into another position out of said path and including a retainer arranged for fitment to said rail;

• wherein said thruster means is of a piston-and-cylinder type, the cylinder of said thruster means is formed integrally with said retainer with its longitudinal axis inclined to the longitudinal axis of said hydraulic unit, the piston of said thruster means is provided with a piston rod, said piston and rod forming said displaceable element, and wherein the axis of said piston rod is parallel to, and substantially offset from, the longitudinal axis of said piston.