Abstract: A restraint assembly for the door-actuating means of a railroad hopper car. The door-actuating means is shifted by the piston of a fluid cylinder between door-closing and door-opening positions. The restraint mechanism comprises a first bracket mounted on the center sill and rotatively supporting a shaft on which a lever is mounted. The free end of the lever is pivotally joined to a first end of a spring assembly. The second end of the spring assembly is pivotally mounted to a second bracket affixed to the center sill. One end of the shaft has a notch formed therein. The door-actuating means has a laterally extending lug. When the door-actuating means is in its retracted door-closing position the restraint assembly will be in an over center restraining condition. Abutment of the door-actuating means lug against the shaft notch will prevent longitudinal shifting of the door-actuating means due to inertia.