A hopper car has arcuate side sheets that are bent over the forming members of the structure to give a generally outwardly bulging shape. The upper margin of the side sheet is kinked inwardly of the radius of curvature of the larger portion of the side sheet more generally, such as may tend to impose a bending moment on the large, relatively thin side sheet panels. This may in turn tend to urge or bias those panels to a bulging position or shape, rather than a sagging, deflected, or inwardly dented position.