To fulfil this condition the inspection technique was optimised in the laboratory. With specially designed probe holders, first demonstrations were carried out on ICE-2 wheel set under practical conditions, i.e. on non-dismantled wheels. In Fig. 3 on the left hand side, the probe holder designed in the laboratory is shown and on the right hand side the industrial designed probe holder. A total of 14 shear wave probes and three straight beam probes are used for the disk inspection.