Fold or corrugation of a bellows or passageway between two artculated vehicles or vehicle parts

The accordion tunnel shrouding between two vehicle sections, e.g. an articulated passenger bus, has an additional pleat unit (20) at the corners with a number of folded pleats to enlarge the structure. At the upper end it is fitted into the peak (11) of the accordion pleat (10), and bonded in position. The lower end of the additional pleat unit is at a height matching the separate pleats (21-23) of the accordion tunnel at the transit into the floor level (30), held in place by a clip frame (25).