Budget-Constrained Rail Electrification Modeling Using Symmetric Traffic Assignment: A North American Case Study

Abstract

We consider a budget-constrained rail network electrification problem with associated changes in costs of energy usage (via path gradient and curvature), operations, and long-term maintenance. In particular, we consider that freight flows on such a network form a user equilibrium. Interactions between electric and diesel trains on the same corridor are represented with nonseparable link performance functions that nevertheless have a symmetric Jacobian. This bilevel formulation is solved for the North American railroad network using a genetic algorithm (GA), incorporating domain-specific insights to reduce the number of solutions that must be considered. We analyze solution characteristics and decision-making implications. Results show that broad connectivity would be beneficial for the most impact. Increasing demand shifts electrified corridors toward the more populous east and gulf coasts, while increased operational costs results in the electrification of routes through mountainous terrains.