Category of Derailment Mechanism and Prevention for High-Speed Vehicle

Vehicle derailment is difficult to explore because accidents are caused by many factors. In this paper, derailment behaviors are divided into three categories: friction-type derailment, structure-type derailment, and nonlinear-type derailment. Each category has unique characteristics. Wheel climb is a frequent form of friction-type derailment, resulting from mechanical and generally dynamical behavior between wheel and rail. Dynamic simulation is an important tool for prediction of friction-type derailment. There exists a critical point during wheel climb, and lateral normal force primarily prevents the wheel's moving up. Structure-type derailment is a result of component failure, appearing as local, then developing into general derailment. Factors affecting the development process, such as failure modes, front wheelset derailment, and vehicle speed, are discussed. Nonlinear-type derailment commonly occurs as impact derailment when the vehicle loses stability beyond a nonlinear critical speed. The critical speed for derailment is derived, and the case of a bifurcation diagram is studied. Although nonlinear-type derailment is sensitive to initial conditions, the possibility of accurate prediction is discussed. DOI: 10.1061/ASCE)TE.1943-5436.0000252. (C) 2011 American Society of Civil Engineers.