Abstract: A wheel set for rails has a divided axle and two wheels rigidly attached to he respective axle section. The axle sections are interconnected in a force transmitting manner by a clutch for adjusting a differential r.p.m. between the two axle sections. However, the clutch components also permit a relative rotation when the clutch is not energized. The clutch has an inner clutch component and an outer clutch component forming a work gap (7.4) between the clutch components. The work gap extends concentrically to the rotational axis of the shaft and is filled with a magnetizable powder for engaging and disengaging the clutch components which are so mounted to the respective axle section that an axial displacement of the clutch components relative to each other is prevented.