Simulation Analysis of Vehicle Derailment in Metro Depot Small Numbered Turnout Area

Objective Small numbered turnouts are widely used in urban rail transit, especially in metro depots, but their large switch angles pose a derailment risk when vehicles pass through them. It is necessary to investigate the reasons for vehicle derailment at the turnout frog positions in metro depot. Method A step-by-step approach is taken to establish wheelset model, bogie frame sub-model, and single compartment model, which are then articulated to link all compartments into a whole-vehicle model. A straight section is set up in front of the turnout to eliminate the impact of vehicle startup. The corresponding track sections of the entire turnout area are obtained through linear interpolation and are imported into the software for calculation. Wheelset lateral displacement, derailment coefficient, wheel load reduction rate are selected as evaluation indicators to analyze the influence law of factors such as vehicle speed, wheel tread type and rail vertical stiffness on train derailment risks. Result & Conclusion The simulation analysis yields the following conclusions: When the vehicle speed is too high, the wheel load reduction rate significantly exceeds the standard, hence it is recommended to control the vehicle speed within 5 km/h while passing through the turnout. When using LMX-type wheel tread, vehicles pass relatively smoothly through the dangerous areas of the frog zone, which helps to reduce train derailment risks. Vehicles are more prone to derailment when passing through turnouts with a vertical rail stiffness of 200 MN/m.