Many railroads and research institutes have developed nodestructive testing methods in order to prevent accidents and remove the wheels from service before they fail. One of the most promising alternative means of performing this type of inspection is the evaluation of the stress on the forged wheel rim by ultrasonic testing. The main purpose of this test is to detect the wheel rim stress variations. MWL Brasil, with UNICAMP (State University of Campinas)'s support, applied a stress analysis method by ultrasonic test, using longitudinal critically refracted waves (Lcr). The magnitude of stress found was compared with simulation in infinite elements presenting consistent results.