Axle drive units with reversing shift ultimately deliver the engine power transmitted through the transmission to the railway track. They drive the axles and make it possible to reverse the direction of travel. They also need to be planned and produced in a project-specific manner. ZF will then revert to a standardized modular system. ZF-axle drive units bevel gear drives or helical bevel gearboxes are modular systems which are easy to adapt to their intended purpose in terma of axle load and ratio. The modular final drive is designed for diesel-hydraulic, diesel-mechanic and diesel-electric multiple units and to be used especially in transmission systems with ZF-Ecomat Rail and ZF-AS Rail units. They operate reliably with or without a reversing stage, with or without direct drive (master & slave) in accordance with customer wishes. Control of the entire reversing shift process is fully automatic and effected by the Rail Drive Control system (RDCS) starting summer 2008.