Electro-hydraulic railcar retarders for controlling the speed of a railcar

摘要

A retarder for controlling the speed of a railcar is provided. The retarder includes a brake and a brake actuator that includes a hydraulic piston-cylinder and a spring. One of the piston and the cylinder acts on the brake and the other of the piston and the cylinder acts on one end of the spring. The other end of the spring acts on the brake. In this arrangement, supplying pressurized hydraulic fluid to the piston-cylinder causes both the piston-cylinder and the spring to move the brake towards a closed position in which the brake will apply braking pressure on the wheel of the railcar. The spring resiliently biases the brake into the closed position to maintain a substantially constant braking pressure on the wheel of the railcar as it moves through the retarder.