Train overturning in high winds

Abstract This chapter considers the effects of high winds on train operation. The various issues that arise from trains in high crosswinds are first outlined and a generic methodology is proposed for the consideration of these issues. Firstly, methods are outlined for determining the aerodynamic force and moment coefficients through the use of full-scale testing, physical model testing and CFD calculations. It is clear that the nature of the crosswind flow around trains at full scale is very complex, and model scale measurements and CFD calculations only provide a limited representation of the full-scale situation. Nonetheless, the force and moment coefficients from such tests are adequate for the overall calculation methodology. Such measurements have been made for a wide variety of trains in many different situations. These are tabulated in Appendix 2 , and this chapter provides a simple method of parameterising the results. A range of methods for simulating the natural wind are then critically presented, and the manner in which these simulations are combined with the force and moment coefficients and models of the vehicle dynamic system are set out to calculate the characteristic wind curve, which is used for train authorisation purposes. A simple methodology for calculating such curves is then described. Methods are then outlined for the calculation of the probability of a wind-induced accident occurring along an entire route. Finally, methods of reducing this accident risk, both through physical interventions and operational strategies, are discussed.