Friction Performance of Brake Disks and Blocks for High-Speed EMU Trains in Cold, Rainy, and Snowy Weather

In order to improve the safety of high-speed train operation in cold weather, the braking performance of a high-speed EMU train in temperature range from -15℃ to 20℃ in rain and snowy conditions was simulated and the causes of decline in braking force and scratching of the brake disk surface were investigated. The results showed that the average friction coefficient increased with increasing braking force. The effect of external hard particles on the friction coefficient varied with the braking speed. When the speed was less than 160 km/h, the friction coefficient increased with increasing speed. When the speed was more than 160 km/h, the external hard particles did not have an obvious effect on the friction coefficient. It was also found that the decline in transmission efficiency of the clamp in severely low temperatures and wet conditions was due to the clamp being covered with snow and becoming difficult to reset, which in turn reduced the clearance of the brake disk and brake blocks. In such a situation, external hard particles or contact between the brake block and disc would result in scratches on the brake disk surface. The research showed that braking for 1 min after every 7 min interval could remove the ice on the brake disk surface and prevent the clamp from being frozen in ice.