Real-time scheduling of freight railroads

This article presents a model for the optimization of freight trains schedules that is intended to be used as part of a real-time control system. The goal of this model is to provide a link between strategic schedules, which might be decided every month, and line dispatching or CAD models which need to know the scheduled arrival and departure times for each train at the ends of each lane at very frequent intervals. An algorithm for the problem along with an efficient heuristic are described and then tested on a portion of a major North American railroad to ascertain their efficiency and efficacy.