Benefits of Dipped Vertical Alignments for Rail Transit Routes

Abstract

Dipped track profiles between rail transit stations can significantly reduce propulsive energy, braking energy, and travel times. This work quantifies their potential benefits for circumstances reflected in various values for dips, speed and acceleration limits, station spacings, and available power. A deterministic simulation model has been developed to precisely estimate train motions and performance using basic equations for kinematics, resistance, power, and braking. For a 1% dip (i.e. a vertical dip equal to 1% of station spacing) in which gradients never exceed 4%, our results show savings (compared with level tracks) exceeding 9% for propulsive energy, 15% for braking energy, and 5% for travel time between stations.