The significance of the wheelbase size to the vehicle lies in that the wheelbase determines the position of the center of gravity of the vehicle, causes the change of axle load distribution of the front axle and the rear axle, and affects the length, comfort and handling stability of the vehicle. The wheelbase of a car is the distance from the center of the front wheel to the center of the rear wheel. Too long and too short wheelbase will affect the performance of the whole vehicle. The wheelbase is divided into fixed wheelbase, bogie wheelbase and full wheelbase. Fixed wheelbase refers to the horizontal distance between the axle center lines at the front and rear ends in the frame of the frame locomotive owner. For the convenience of curve, the fixed wheelbase should not be too long. Bogie wheelbase refers to the distance between the axle center lines at both ends of the bogie. Full wheelbase refers to the horizontal distance between the axle center lines at the front and rear ends of the locomotive.