Rolling contact fatigue study of railway rails

This work analyses the wheel-rail interaction in terms of rolling contact fatigue (RCF).For this purpose, a full scale testing machine was designed and built in order to apply the loads and boundary conditions appearing in the railway (up to 30 tons per wheel, application of lateral load in bends, inclination, angle of attack, presence of dust, water…) Eight tests were performed under different load conditions and rail grades and RCF cracks were generated after 50000 to 100000 cycles.The occurrence of cracks was determined by magnetic particle inspection at regular intervals in the course of the tests.When the non-destructive inspection showed the existence of cracks, the test was stopped and the rail longitudinally and transversally cut to perform a metallographic analysis in order to know the nature, growth direction, shape and size of the cracks.The cracks generated in the laboratory tests were identical to those seen in RCF affected railways and significant variations were found in the behavior of the different rail grades.The proposed test was able to simulate the damage produced in rails by RCF and allows the comparison of the fatigue behavior of different rail grades under highly controlled conditions.