Commercial vehicle structure with carriage held in guide rail

The structure has a roof (3), and a running rail attached to the roof. A carriage (9) is arranged in the rail for moving loads along the rail. The carriage has a roller (14) that comprises a running surface (23) rolling-off at a running surface (21) of the rail. The running surfaces of the roller and the rail comprise a contour outwardly curved corresponding to each other. The rail has a vertically, downwardly-pointing slot for accommodating a connection element (20) between the carriage and the loads, where the rail is inserted into a roof panel of a box structure.