Wheels - Experiences with wheels and composite brake blocks (K) in service

As part of work by UIC, the wheel profiles were assessed based upon service tests on freight wagons with composite brake blocks. Service tests are performed by the UIC railways DB AG, FS, MAV, SJ, SNCF and SBB. The data from the 3-year service test at SBB was used for assessment. The investigations showed that the roughness levels of the wheel running surfaces following the use of the composite brake blocks over extended distances resulted in permanently reduced noise emissions in comparison to that for cast-iron blocks. Furthermore, it was found that the different qualities of composite brake blocks had different effects upon the geometric and geometric contact interactions between wheelset and track or wheel/rail.

New composite brake blocks must be subject to the requirement that the wheel profile must be characterized to a significant degree by the wheel/rail contact.

The comparison between cast-iron and composite brake blocks has shown that both in-service and reprofiling wear differ. The increased in-service wheel wear can be compensated by a lesser diameter reduction during reprofiling.