Full-scale railway wheel flat experiments

Extensive field experiments (the 'Silinge wheel flat experiments') with a m oving train have been designed, performed (at Silinge) and evaluated. More than 200 wheel flats were formed under controlled conditions involving diff erent wheel loads, train speeds and sliding durations, and the friction coe fficient between the wheel and the rail was also varied (and indirectly mea sured). Samples extracted from flats of the tested wheels have been metallo graphically examined with respect to phase transformations and cracks. A nu merical model for wheel flat prediction has been qualitatively verified and quantitatively calibrated. In the experiments, martensite was found beneat h all flats and cracks were observed in most cases. It is concluded that th e risk for future spalling should be considered for all wheelsets with flat s. A damaged wheelset should be taken out of service as quickly as possible . When reprofiling the wheels, all martensite and an additional layer of se veral millimetres should be machined off.