The device (1) has a platform (2) held by a carriage (5) and comprising a bridge plate (3), where the carriage is supported in a housing of a vehicle. The carriage is connected with the platform through hinged brackets (4), and carriage has a drive for connecting with the brackets. A rod arrangement (14) is coupled with one bracket and stays in effective connecting with a pivot axis (20) for pivoting the bridge plate. The arrangement is connected with a positive guide (43) for a guiding unit of a hand rail (40) for folding-in and folding-out of the hand rail.