Stresses on running gear - Running surface defects on wagon wheels and their impacts on the stresses exerted on running gear and the dimensioning thereof

As part of the study of the damage caused by running surface defects, analyses were performed based on the results of loading and acceleration measurements recorded on wheels, axles, axle boxes, bogie frames and parabolic springs.

These analyses indicate that local tread collapse has the most negative impact on the running gear examined. Wheel flats are the second most damaging factor. Spalling and out-of-rounds have little impact.

In addition, it appears that defect length measurement is a source of error and that depth measurement is sufficient to characterize the impact of defects on stresses exerted on running gear in service. It is therefore recommended that local tread collapse and wheel flats be assessed on the basis of the depth measurement in the context of maintenance.

Finally, this analysis confirms the validity of the depth criteria of 0.6 mm for local tread collapse and 1 mm for out-of-rounds. It is to be noted that axle box acceleration remains below 200 m/sec ² for these criteria.