1. Key Laboratory of Traffic, Safety on Track of Ministry of Education, School of Traffic and Transportation Engineering, Central South University, Changsha 410075, P. R. China
2. Joint International Research, Laboratory of Key Technology for Rail Traffic Safety, Central South University, Changsha 410075, P. R. China
3. National and Local Joint Engineering, Research Center of Safety Technology for Rail, Vehicle, Changsha 410075, P. R. China