Measuring Methods of Radius of Curvature and Tread Circle-Fitting Studies for Railway Wheel Profiles

A railway wheel profile consists of short arcs with complex radii curvature, and wear leads to changes in the profile’s radius curvature that ultimately affects dynamic performance train. To track evolution in-service curves, new foundry profiles need be measured. This study proposes a series algorithms calculation methods for measuring profiles. Firstly, was estimated U-chord method, segment points were located. Secondly, discrete derivative method Two-Arcs Tangency Constrain (TATC) used calculate fitting circle radius, respectively. The experimental results three types showed curves precisely divided according maximum errors calculated compared standard values by TATC 2.50% 0.42%, Furthermore, two measurement methods’ performances repeated experiments analyze uncertainty.