An innovative degraded adhesion model for railway vehicles: development and experimental validation

The realistic description of the wheel-rail interaction is crucial in railway systems because the contact forces deeply influence the vehicle dynamics, the wear of the contact surfaces and the vehicle safety. In the modelling of the wheel-rail contact, the degraded adhesion represents a fundamental open problem. In fact an accurate adhesion model is quite hard to be developed due to the presence of external unknown contaminants (the third body) and the complex and highly non-linear behaviour of the adhesion coefficient; the problem becomes even more complicated when degraded adhesion and large sliding between the contact bodies (wheel and rail) occur. In this work the authors describe an innovative adhesion model aimed at increasing the accuracy in reproducing degraded adhesion conditions. The new approach has to be suitable to be used inside the wheelrail contact models usually employed in the multibody applications.