Improved spiral geometry for high-speed rail and predicted vehicle response

摘要

This article compares two railroad curve transition spiral shapes with respect to their dynamic performance. The shapes compared are the traditional linear spiral and an improved spiral devised to provide good dynamic performance. The improved shape is attractive, both because it gives improved dynamic performance and because it flows from a better way of thinking about spirals. The comparison is based on simulation of the operation of a rail vehicle over an improved spiral and over the corresponding traditional spiral. The simulations were done using the NUCARS simulation program and a model of the Amtrak Acela passenger car.