Bidirectional loaded traffic effect was investigated for heavy haul railway lines, using a coupled analytical and numerical method. A tridimensional elastoplastic finite element model of a rail was developed to obtain the stress and strain distributions. Hertz and Kalker theories were used to estimate the contact pressure and tangential forces on the wheel/rail surface. The resulting critical stress tensor was used to investigate the crack nucleation with Dang Van and Findley’s criteria. The results reveal that the plastic strains stabilize early, the resulting stress range is similar, and that the bidirectional loading affects the life to crack nucleation Ver menos