Tram Emergency Braking Control Optimization Method Based on Magnetic Rail Braking Friction Characteristics

［Objective］ The emergency braking of trams is significantly vulnerable to the characteristics of magnetic rail braking. With changes in train load and train operating speed, the instantaneous deceleration of trams can fluctuate greatly. At low operating speed stage, the instantaneous deceleration of trams is prominent, which can cause substantial braking impact. Therefore, it is necessary to investigate an optimized emergency braking control method for trams. ［Method］ Through magnetic rail braking tests conducted on a specific tram line in China, the impact of various train load conditions and initial braking speeds on the magnetic rail braking friction characteristics of trams is examined. By fitting the test data, a characteristic function describing the variation of magnetic rail braking friction coefficient with speed is obtained. Based on this function, an optimized emergency braking control method for trams is proposed. ［Result & Conclusion］ During braking, the sum of the electric and hydraulic braking forces can be adjusted in real time according to the load and speed conditions of the train. This optimization method ensures that the combined braking force of electric, hydraulic, and magnetic rail braking remains relatively stable throughout the braking process, and the instantaneous deceleration during emergency braking remains constant. The method also effectively mitigates issues such as large fluctuations in instantaneous deceleration during emergency braking and excessive longitudinal braking impact at low train operating speed.