EFFECT OF RAIL LIFT-OFF ON THE ANALYSIS OF RAILROAD TRACKS

The standard analysis of bending stresses in the rails of a railroad track is based on the assumption that the track can be modeled as a beam attached to a Winkler base. However, it was observed in the field that when a locomotive or a loaded car passes over a track, sections of the rails often lift off from the base a short distance away from the wheels. The purpose of the present paper is to determine under what conditions lift-off will take place for one and for two axle trucks and then to establish the effect of this lift-off on the rail stresses and on the forces the rails exert on the ties, for the tracks currently in use. The analysis is performed by modeling the track as a rail that rests on a Winkler base and is subjected to vertical wheel loads.