Curve squeal in the presence of two wheel/rail contact points

A real case of a city tramcar generating very high curve squeal noise levels has motivated research in this area considering the simultaneous presence of two contact points. In this paper, available measurements are summarised in a qualitative manner in order to highlight the most important frequencies involved and a theoretical model in the frequency domain is developed with the aim of predicting curve squeal tones. Good matching is found between numerically predicted and measured unstable frequencies and a peculiar shift toward higher frequencies is found both in measurements and predictions.