Abstract: An edifice such as a sports stadium is adapted for open use during good weather as well as for covered use during poor weather by having at least one movable roof member. Each movable roof member includes a transport mechanism that is constructed and arranged to permit the roof member to move in a predetermined path with respect to the underlying structure of the edifice. The transport mechanism includes structure for supporting both ends of the roof member, which bridges an otherwise open area of the edifice. In order to permit some flexure and movement of the roof member with respect to the underlying edifice, as will inevitably occur as a result of natural forces such as winds, orientation structure is provided for maintaining the transport mechanism in a predetermined orientation while simultaneously permitting a limited amount of movement of the roof member in a direction that is nonparallel to the predetermined path of movement.