1. Technology and Equipment of Rail Transit Operation and Maintenance Key Laboratory of Sichuan Province, Chengdu, P. R. China
2. School of Engineering, University of Liverpool, Liverpool, UK
3. Key Laboratory of Testing Technology for Manufacturing Process, Southwest University of Science and Technology, Mianyang, P. R. China
4. Tribology Research Institute, School of Mechanical Engineering, Southwest Jiaotong University, Chengdu, P. R. China