Analysis and Remediation Strategies for Rail Profile-induced Train Hunting Instability in Rail Transit Turnout Area

Objective Causes for train hunting instability in rail transit turnout areas are complex, usually related to turnout irregularity, vehicle state, wheel-rail relationship and other factors, seriously affecting driving comfort and threaten driving safety. Therefore, it is necessary to analyze the hunting instability caused by the rail profile in rail transit turnout areas and propose remediation measures. Method Taking the train instability in the No.3 and No.5 turnout areas of a certain station as an example, the field situation is analyzed and rectified from perspectives of train dynamic operation status, rail surface condition, rail profile characteristics and wheel-rail relationship. A comprehensive remediation measure integrating profile design with rail grinding is proposed. Using actual line and vehicle parameters, a vehicle-track coupling system is established to design optimal rail grinding target profiles suitable for the corresponding line. Rail profiles in the rail database are matched with measured vehicle profiles respectively, and the wheel-rail static action analysis and calculation are carried out to obtain the rail quality index GQI. The wheel-rail system dynamics under different rail profiles is calculated with the vehicle-track coupling system dynamics model, to obtain the relevant wheel-rail dynamic action evaluation index is obtained, so as to calculate rail design profiles and that at the corresponding sharp base combination section and grind rails according to the design. Result ＆ Conclusion Rail profile and equivalent conicity are important causes of train instability. After inspection, it is found that train operational performance has been greatly improved through the comprehensive remediation approach integrating profile design with rail grinding.