Full-scale railway wheel flat experiments

Abstract

Extensive field experiments (the ‘Silinge wheel flat experiments’) with a moving train have been designed, performed (at Silinge) and evaluated. More than 200 wheel flats were formed under controlled conditions involving different wheel loads, train speeds and sliding durations, and the friction coefficient between the wheel and the rail was also varied (and indirectly measured). Samples extracted from flats of the tested wheels have been metallographically examined with respect to phase transformations and cracks. A numerical model for wheel flat prediction has been qualitatively verified and quantitatively calibrated. In the experiments, martensite was found beneath all flats and cracks were observed in most cases. It is concluded that the risk for future spalling should be considered for all wheelsets with flats. A damaged wheelset should be taken out of service as quickly as possible. When reprofiling the wheels, all martensite and an additional layer of several millimetres should be machined off.