The Relationship between Contact Angle Difference and Equivalent Conicity of High-Speed EMU

This paper studied the relationship among the linear model of wheel/rail characteristic parameters, the contact angle difference, the equivalent conicity and roll angle. The standard and worn profiles of S1002CN, XP55 and LMA were matched with 60 kg/m rail separately. The results of the study show that the ratio of contact angle difference to equivalent conicity changes linearly along lateral wheelset displacement within 5mm. Taking rolling angle into consideration, the contact angle difference and equivalent conicity in nominal position (3mm) display a linear relationship. Just considering the contact angle difference and roll angle in the fitting formula for the wheel/rail linear model calculation, the quasi-linear calculation of the critical speed could be more accurate. Therefore, the wheel/rail linear model characteristic parameters roll angle and the contact angle difference in the nominal position have certain effect on vehicle dynamic performance like equivalent conicity.