Abstract: A cover for closing the opening of a railroad hopper car which is adapted to be hingedly coupled to the car is the subject of the invention. The cover is constructed so as to provide a degree of flexibility which increases the ability of the cover to withstand downward vertical forces. The cover comprises a member which presents a generally vertical side wall section that extends around the car opening and a top wall that is integral with the side wall and extends over the opening. The cover is formed in a generally arcuate configuration along a line passing through a horizontal plane and extends away from the plane at a first angle of curvature. A generally flat area along the top wall of the cover is formed in a generally arcuate configuration along a line passing through the same reference horizontal plane while extending away from this plane at an angle of curvature that is greater than the first mentioned angle of curvature.