Abstract
The treads of railway wheels are subject to high load and wear and their integrity is essential for the safety of the whole train. Visual inspections and optical gauging of the wheel profile are commonly applied for high-speed trains. AUROPA III is a rather new ultrasonic inspection system for the fast and early detection of crack-like defects in the tread of railway wheels. The system enables the inspection of the whole circumference of the tread while the train passes over stationary ultrasonic probes at speeds of up to 15 km/h. EMAT probes are used which do not require liquid couplings. The ultrasonic wave propagates as a surface wave in the near-surface zone of the tread; crack-like defects in this zone are detected by echoes and attenuation of the transmitted wave. This system can inspect all the wheels of a train in a few minutes and allows a fast screening of the condition of the tread.