In a welding station, particularly for motor-vehicle bodies, the elements to be welded are locked in a precise position by locking devices carried by locating gates. There are provided a number of parts of locating gates, corresponding to the number of different types of structures to be welded on which the station must operate. The gates are mounted on powered carriages which are guided longitudinally on both sides of the conveyor line to allow the pair of gates which are in the operative position to be rapidly interchanged. The elements of the structure to be welded reach the work area suspended to a hook, without being preliminarly connected to each other.