WHEEL LOAD AND WHEEL DIAMETER FROM THE POINT OF VIEW OF STRESS ON THE MATERIAL IN THEORY AND IN PRACTICE

A report submitted at the 12th meeting dealing with Modern railway rolling stock, held in Graz. It consists of a collection of formulae and data enabling conventional pressure in the wheel metal to be established, in accordance with the diameter of the wheels and their load. This pressure, calculated with the help of the Hertzian theory, depends on the normal and vertical efforts exerted in the contact surface between wheel and rail. Compared with the undefined limit of fatigue strength, it enables an estimate to be made of the distance which the vehicles are able to cover without risk of deterioration of the wheel treads. The dimensions of the contact surface, and its evolution during deformation, caused by wear, of the wheel profile, being difficult to establish, it is advisable to prepare the estimates on the basis of similarities with the characteristics of wheels subjected to stresses in a comparable manner, and whose behaviour in service is known.