Wheel profiles for freight wagons in Sweden
Freight wagons in Sweden use the S1002 wheel profile, developed in a benchmark back in the 70s. This profile is not common in European countries where each operator has its own modified profile, and it is not a specific wheel profile for Swedish conditions. Thus, the freight vehicle fleet has high maintenance costs due to wheel reprofiling and has some low-frequency instability related problems.
The purpose of this research project is to create a wheel profile suitable for freight transport in Sweden, which reduces the reprofiling costs and improves the low-frequency instability behaviour of the vehicles. This profile should reduce the uniform wear and the material to be removed in each reprofiling, and increase the critical speed of unladden vehicles. The first reduction generates a higher running distance between reprofilings, and the second one ensures more reprofilings for each wheelset before it can no longer be used.
In the first phase of the project, the wear calculation methodology developed at the Division of Rail Vehicles at KTH must be validated for freight transport. A vehicle running in a specific line will be chosen, and the wear predicted by a computer model will be validated with experimental results. In this phase the wear caused by block brakes must be included, which will be very influencing in the wheel profile. Thus, a block brake wear calculation model will be developed and validated against experimental measurements.
After the methodology has been validated, the wheel profile will be optimized. This new profile will be used in future vehicles, so first of all the future freight train fleet will be predicted. The wheel profile will be optimized using a genetic algorithm for each of the vehicles included in this future vehicle fleet.
The next step will be to install wheelsets with this new profile in some freight vehicles and do a follow up in order to detect further improvements and validate experimentally the benefits of this optimized profile.