Abstract
Wheel "flats" are a major source of problems in railway systems since they cause strong wear both in the infrastructure and in the train vehicles. In this work we present field tests concerning the application of Fiber Bragg Grating (FBG) sensors for the detection of out-of-roundness in high-speed train wheels. Wheel flats are shown to cause high-energy impacts on the rails which can be monitored using FBGs located in the rails. The results point out a great potential of this technology for the development of wheel flat detection systems.