Abstract: An upwardly-acting door structure is adapted to close an access opening of a body member, such as an automobile-carrying railroad car. The door structure includes a stationary track on either side of the opening, movable tracks mounted for upward and downward movement along the stationary tracks, an upper panel mounted on the movable tracks, a lower panel mounted to move upwardly and downwardly along the movable tracks at twice the speed, flexible chains arranged to interconnect the lower panel with the movable tracks, torsional springs arranged to counterbalance and support the aggregate weight of the raised movable tracks, and handles operatively arranged to raise and lower the movable tracks. The upper and lower panels may be raised to uncover the access opening, or lowered to cover the access opening.