Abstract: Method and apparatus for the detection of defective track wheels on rail vehicles such as carriages and/or locomotives, whereby an electromagnetic beam such as a laser beam (9) is directed towards the wheel (5) in a direction substantially at right-angles to the plane of the wheel while the carriage and/or the locomotive is running. A series of signals are recorded corresponding to electromagnetic beams reflected from the wheel (5) substantially at right-angles to the plane of the wheel, and a measurement is carried out of the Doppler frequency change between the transmitted beam (9) and the reflected beam. On the basis hereof, a signal processing is effected for the determination of the vibration pattern of the relevant wheel, and a determination of the condition of the relevant wheel is carried out on the basis of the vibration pattern.

Abstract: An apparatus (1) for the scanning of a profile, e.g. the cross-sectional profile of a train wheel (2,3), comprises a stationary part (11) which supports a first arm (22) and a second arm (23), the ends of said arms being coupled together by means of angle-encoding joints (20,21). One of the arms (23) comprises a free end with a measuring wheel (24) which is arranged to be moved in contact with the profile which is to be scanned.Both of the Joints (20,21) are electronic angle encoders which are coupled to a portable computer via an interface circuit.