A Study on Wheel Climb Derailment

4th Report, Measuring Method on the μ Value Between Rails and Wheels

Abstract

Under the critical condition of a wheel climb derailment, the friction coefficient on the contact point position between a wheel flange and a rail is said to seriously affect on the occurrence of the derailment. However, the site of the contact point position is so variously and so complicatedly transferred on the rail side according to the rotation of the wheel set that it is said to be impossible to quantitatively and exactly evaluate the coefficient. At the critical derailment condition, the relation between the friction coefficient and the wheel climb derailment coefficient is shown by the Nadal's equation, and the critical conditions can identify though the investigation into the difference between the theoretically calculated wheel climb-up value and the practically measured one. Employing a model truck and a model track, experiments were done to investigate the friction coefficient using the above mentioned method. As the result of experiments, it was found that the friction coefficient on a dry rail was nearly equivalent to the adhesion coefficient.