Railway Alignment Optimization Considering Lifecycle Costs

Abstract

The problem of railway alignment optimization is studied, with particular attention given to computing lifecycle costs while considering train speed profile optimization and traffic demand. Recurring expenses, including energy, user, and maintenance costs, are considered in the lifecycle. A novel speed profile optimization method for the energy-efficient operation of trains is developed and incorporated in a simulation model, which considers regenerative braking energy. According to the train motion simulation results, the energy consumption and travel time per round trip are obtained, based on which the recurring costs are computed by taking traffic demand into account. The horizontal and vertical alignments are jointly optimized with the train speed profile based on the computed recurring and initial expenses, which include rolling stock, earthwork, bridge, tunnel, right-of-way, and length-dependent construction costs. A case study and sensitivity analyses are presented to discuss the impacts of traffic demand on the optimized railway alignment. The effectiveness of the speed profile optimization method is demonstrated by comparing its simulated results with those without speed control.