Brake Performance Deficiency of UCT (Unaccompanied Container Transport) trains

As one of the results of a large stopping distance measurement campaign, SBB found that UCT trains (carrying containers, semi-trailers, swap bodies) have on average a 15% lower braking performance (braked weight percentage lambda) than the expected one according to the operational braking calculation of the trains, resp. 10% lower than the operational value written on the driver s braking sheet. Other freight trains didn t have this problem. In Austria and Switzerland, since 2014, according to the operational regulations, a 10% reduction of the braking weight percentages of these trains has to be applied. Possibly, other countries (NSA s) will follow. But this measure doesn t fit into the UIC braking performance system and has to be withdrawn as soon as the problem has been properly solved on a technical base. It is not acceptable, especially for ETCS, that there exists a class of international freight trains that systematically do not fulfil the UIC braking performance requirements. Therefore, the goals of the project are:

• Determine the exact causes of the phenomenon in question
• Avoid/withdraw operating restrictions for combined transport
• Potentially (depending on cause):
  • revise design rules for self-adjusting load-proportional braking systems
  • amend vehicle approval / type test (brake assessment) rules with a view to improving coherence between nominal and actual braking performances
  • adapt maintenance rules