To eliminate sufficiently the influence of the change of the length of a vehicle which is caused by thermal expansion by a method wherein the length of an adjusting element provided between two adjusting units is reduced by a value corresponding to the thermal expansion at the time of temperature rise.

Linking parts 2 and 2' are provided between one vehicle part 1 and the other vehicle part 1'. An adjusting element 3 is provided between the linking parts 2 and 2'. At the time of temperature rise, the length of a specified interval between the point A and point B of the adjusting element 3 is reduced by the value of the thermal expansion of the vehicle parts 1 and 1' between two adjusting units. With this constitution, a maximum driving force is consistently available and, as the influence of the heat can be eliminated sufficiently, the vehicle parts of a train can be relatively positioned with spacings therebetween.