An Approach to Wind Blow-Over Risk Reduction at BNSF Railway

FRA derailment statistics between 1996 and 2009 show an average of 13 derailments each year industry-wide are attributed to extreme winds, roughly 7 of which result in vehicles blowing over and derailing. BNSF Railway has developed a hybrid process to identify critical crosswind speeds for various types of railcars to mitigate future blow-over derailment risk. The method uses computational fluid dynamics to compute the wind effects based on the car envelope. These wind effects are simplified in an empirical spreadsheet tool for various wind and train speeds, and wind heading angles. CFD analysis and reduction into the empirical spreadsheet tool have been completed for alimited set of car types. With the resulting external wind loads, vehicle dynamic simulations are used to evaluate the propensity for wheel unloading. Both VAMPIRE® and NUCARS® dynamics routines were used for various parts of this study. In all cases, the wind onset has been assumed to ramp from a zero to full wind condition which remains steady from there forward. The main paper will cover several steps within this project: aerodynamic investigations and generation of appropriate load sets, preliminary and secondary vehicle dynamic simulations, and simplified train operating guidelines proposed thus far. The paper is summarized with a discussion of how these results may be applied to further mitigate wind blow-over derailments in terms of operating rules and the operating environment. An appendix is provided which outlines the relationships between the CFD wind loads and assumed train simulation speeds.