Abstract: A wagon is provided with a superstructure removably attachable to the bed and which includes a pair of sidewall assemblies each having a sidewall to which is pivotally attached a roof member. Power devices on each sidewall are actuated to displace the roof members between an abutting closed position overlying the wagon bed, and an open position fully above the sidewalls and laterally outside the area above the bed. Alignment and latching devices on each roof member are automatically cable controlled during the actuation of the roof members. The opening limits of the roof members is regulated by hinge plates which provide abutments against the sidewalls. An end of the wagon is closable by a pair of removable doors and when the roof members are open, the added elevated cargo space therebetween may be closed at the end of the wagon by a removable end gate removably attached to and spanning the two opened roof members.