A hopper car discharge outflow is controlled by closure members, at least one of which is movable. The doors are hingeless, being mounted on four bar linkages, such that the distal edge of the doors sweeps predominantly horizontally while the proximal edge of the door moves predominantly upwardly. The doors move through noncircular arcs, such that the size of the vertically projected door opening is abnormally large compared to the clearance heights of the door. The doors are driven by a transverse drive linkage that is driven by a transversely mounted actuator. The actuator is mounted in an accommodation in the lee of slope sheets between adjacent hoppers in a mid-span portion of the car. Drive from the actuator is carried to a pair of symmetrically mounted doors through drive train linkages. The drive train includes longitudinally extending torque tubes that transmit drive to both fore and aft ends of the door assemblies. The car also has a lost motion secondary lock system, an alternate manual drive door opening and closing drive train, and abnormally high side sills and a center sill that passes clear through the discharge sections at a height clearly lower than the upper margin of the discharge sections.