The thermal capacity of the wheels puts a limit to railway tread braking systems. In the previous project SD4 “Control of block braking”, the heat partitioning between brake block, wheel rim and rail was studied. In project SD7, the range of tread braking applications to be studied will vary from light, medium and heavy metro applications to mainline coach or freight locomotive applications. However, the focus will be on wheels for metro applications where frequent stop braking occurs.

With exception for the drag braking cases described in the standard EN 13979-1 there are no known standards or guidelines in the public domain regarding the thermal capacity limits for wheels. There is thus a need for development of a verifiable set of guidelines and assessment criteria. In-service rejection criteria (e g, maximum residual stress levels) for wheels that have endured a (potential) overheating event also require consideration. The present project should develop methods and provide data that can form a basis for future design guidelines. Mathematical modelling, rig experiments and field tests will be included.