Wear and rolling contact fatigue interaction in rolling/sliding contact is an important topic in the research on structural integrity of rails and railway wheels. Wear is in competition with rolling contact fatigue, as it removes surface material layers, reducing cracks length and hindering their propagation. Cracks nucleate by accumulation of cyclic unidirectional plastic strain (ratcheting). In this paper a model for ratcheting assessment is discussed and applied to the UIC 900A steel, after a calibration based on experimental results. The experimental tests allow also a characterization of the crack formation condition for this material. By this model, a computer program is developed in order to simulate in a very short time the effect of a large number of load cycles, providing a tool for predicting crack formation and propagation rates.