1. Ph.D. Student, State Key Laboratory of Rail Traffic Control and Safety, Beijing Jiaotong Univ., Beijing 100084, China.
2. Professor, School of Traffic and Transportation, Beijing Jiaotong Univ., Beijing 100084, China.
3. Associate Professor, State Key Laboratory of Rail Traffic Control and Safety, Beijing Jiaotong Univ., Beijing 100084, China (corresponding author).
4. Director, Maintenance-of-Way Dept., Lanzhou Railway Bureau, Lanzhou 730000, China.