Calculation method of wheel/rail adhesion coefficient in complex operating environment

Wheel-rail adhesion coefficient is the key index to describe the adhesion state between wheel and rail. It is under the influence of plenty of factors and has complex change characteristics. This paper has generalized the main factors that affect the adhesion coefficient and their research status. Influence of different factors were discussed and determined using grey correlation degree based on limited laboratory data. The calculation method was put up to solve the adhesion coefficient for complex environment, and the average relative error was proved to be 6.38%. Probabilistic model of the adhesion coefficient was designed and built. HXD1 locomotive running on a certain railway line was taken as the research object, and the sample of the adhesion coefficient was analyzed by chi-square test and Kolmogorov-Smirnov test. The result shows that the adhesion coefficient suits the Weibull distribution best. The calculation adhesion coefficient in traction calculation was predicted as 0.232 where the cumulative distribution function is 50%, and the average value fits the physical definition well.