This thesis describes an investigation of an electrical method for detecting cracks in railroad wheels. The method involves measurement of the magnetic field of a current passing through the wheel from the axle to the rail contact point. Cracks cause disturbances in the current distribution, and therefore in the magnetic field. The principal part of this thesis describes an experiment using scale model wheels in a laboratory. The results of this experiment show that the magnetic deviations are large enough for detection of most faults. Several problems must be solved before a practical system for use in railroad yards can be built, but this thesis has demonstrated that such a system is possible.