High pressure, low slip, radial piston pumps with a gear pump powered stroking mechanism supply equal volumes to each of the two car dumping jack cylinders. The circuit has safety and control features which are required by many oil-powered machines.
Three major design problems are solved in the construction of a hydraulic power system used to dump slag loaded railroad cars. Keeping two cylinders moving together regardless of varying loads, eliminating possibilities of shock in the system because of the large mass being handled, and providing rigid piping on oscillating cylinders are all accomplished in the design.