The tribology of conventional wheel on rail system is a fundamentally a very important research subject, which is very specific to railway. We have developed an instrument for measuring friction coefficient of wheels, which is as called "µ-tester." The measurement procedure of the µ-tester is as follows: 1) Its roller contacts a measuring plane by a spring. 2) The roller slide-rotates on the measuring plane by pulling a string twisted around the boss of the roller. 3) we calculated the value of friction coefficient from the pulling force and the normal load, which sensed by load cells. The µ-tester is capable of measuring various surfaces such as a rail and a roller rig in addition to a wheel by exchanging a fixture. The values of friction coefficient of a rail as measured by the µ-tester were in general consistent with those measured by a rail tribometer. This paper describes as outline of the µ-tester and some of the experimental results of friction coefficient of wheels as measured by the µ-tester.

Copyright (c) 2006 Railway Technical Research Institute