A method and system for determining rail defects. The method and system receive route performance measurements from a vehicle system traveling along a route and normalize the route performance measurements based on one or more characteristics of the vehicle system. The method and a system also determine a defect for a segment of the route based at least in part on the normalized route performance measurements with respect to a threshold bandwidth corresponding to the segment. The method and system also examine velocity differences in a vehicle speed of a vehicle and the angular speed of the axles and/or wheels of the vehicle system traveling along a route to determine if the route is damaged and/or to identify the location of the potentially damaged section of the route. The differences may represent wheel creeps of the vehicle system.