PURPOSE: To facilitate the railway transportation of a trailer without using an additional carrier by coupling the front and rear parts of the trailer with two trucks which can travel on the railway.

CONSTITUTION: At the both ends of a trailer vehicle 6 of the trailer 7 are provided an engaging projection 13 respectively for engaging with the truck 8. The projection 13 has a frame fixing pin hole 14 through which a pin of the truck 8 is inserted. The trailer 7 is provided with a connecting part 16 which engages with a connector 15 of the truck 8 to obtain a fixation of the trailer 7 to the truck 8. When the trailer 7 is mounted on the trucks 8, while an auxiliary leg 11 is lifting up the trailer 7 on the reilway, the trucks 8 are placed under the trailer 7 and then the trailer 7 is descended on the trucks 8 and fixed thereto. This enables a reilway transportation of the trailer and eliminates a use of any additional carrier means.