In cooperation with W.S. Werkstoff Service GmbH, we offer a testing concept as an alternative to x-ray diffractometry to test residual stress. The WS-RS system is able to conduct residual stress testing inside the wheel rim’s entire volume using ultrasonic technology. The polarised ultrasonic waves can detect both surface and internal stress of the test piece without damaging it. Wheels of good waggons are a practical application example, as they have to exhibit tangential residual compressive stress in the wheel rim after manufacturing (acc. to DIN EN 13262). Monitoring this residual stress consistently is crucial to prevent part failure, e.g. as a consequence of thermal transverse cracks. For this, ultrasonic testing enables reliable control. Due to its flexibility, the WS-RS is not only suitable for train wheels, but also for a number of other parts and materials. Additionally, this method can localise and analyse stress inhomogeneities, which is highly important in quality assurance and control.