Abstract The law of optimal conformity, which is characterized by stable wear contours and profiles, was applied to the development of a new wheel profile for diesel and electric locomotives. The proposed wheel profile allows improved guidance on curves, extends the interval between successive tread re-profiling and reduces contact stresses and wear rates. The proposed wheel profile is expected to ensure the optimum use of wheel and rail materials and to effect considerable saving in foreign exchange. Design considerations have minimized the incidence of hot boxes on BG four-wheeler wagons fitted with plain bearing axleboxes. Re-design of lead plugs used in steam locomotive boilers has effected considerable material conservation.