Basic experiments on measurement of traction coefficient between rail and wheel when traction motor torque changes

Abstract

Railway vehicles use rolling contact between wheels and rails to obtain propulsion, which results in low running resistance and excellent energy efficiency. However, since the friction coefficient between the wheel and the rail is small, and it becomes smaller in bad weather such as rainy weather, the wheel tends to slip. Also, when slipping, the propulsive force acting between the wheels and rails tends to be small, so sufficient propulsive force cannot be obtained, which causes a delay in train schedule. In order to prevent slipping, in the case of an electric vehicle, a method (re-adhesion control method) is known in which the main motor torque is controlled to control the rotational force of the wheels to prevent slipping. In this paper, we report the fact that we investigated the influence on the traction coefficient using a mini-model electric vehicle in order to utilize it for the design guideline of re-adhesion control considering the movement of the vehicle body.