Abstract: A centering apparatus for bi-directionally pivotable hopper doors. The apparatus is coupled between a frame of a hopper car and a bell crank of a hopper door. The apparatus includes a housing with a piston extending from one end. An end of the piston within the housing includes a piston head. A pair of coil springs are disposed within the housing on opposite sides of the piston head and counteract one another to bias the piston head toward the center of the housing and thus bias the hopper door toward a closed state. In a second configuration the apparatus includes a double-acting actuator with a pair of independent piston assemblies. An actuation system coupled to the actuator maintains the actuator and an associated hopper door in a closed position in a normal state and returns the hopper door to the closed position upon a failure in the system.