New track shift limits for high-speed rail

摘要

1. On the basis of TREDA model predictions and track shift testing at the Transportation Technology Center, and approach for new track shift safety limits are presented here, including new Prud'homme type limits. They are based on the "onset of nonzero deflection" criteria i.e. loads which produce no track lateral shift with a large number of axle passes. For modern highspeed tracks, this formula is more appropriate than the Prud'homme formula, which is conservative in many cases. For non-uniform axle lateral loads, the Prud'homme formula is not applicable. 2. The track residual deflection analysis (TREDA) model has been validated through field tests, and can be used to evaluate track shift lateral response under moving loads accounting for many track conditions/parameters. As shown, the model can easily be applied for the development of safety limits. 3. The safety limits recommended here based on theoretical model predictions are currently undergoing validation tests before final safety recommendations are made.