PURPOSE: To provide a transportation vehicle which can be moved from a place to another place by a tractor with on-road tires, and with which a trailer can be connected to an engine or a leading train in utilization of a railway by providing a coupling means to releasably connect the transportation vehicle to the engine or leading train, and a coupling means to releasably connect the trailer to the transportation vehicle.

CONSTITUTION: A transportation vehicle 10 connected to an engine tractor 14 and matched for on-road use is positioned to a position to be connected as a first train of a convertible trailer on a railway truck. In the transportation vehicle 10, an on-road wheel axle unit 34 is lowered to a ground engagement position, and a gooseneck coupler 36 is pulled from the transportation vehicle 10 to be connected to a fifth wheel of the tractor 14. On the contrary, in the transportation vehicle 10 formed for a railway traveling mode and disposed between a trailer 12 and an engine 16, the on-road wheel axle unit 34 is risen, and a rail wheel axle unit 40 is placed on rails 38. The gooseneck coupler 36 is retracted, and the transportation vehicle 10 is connected to the engine 16 through a railway coupler 42.