Assessment of Advanced Dispatching Measures for Recovering Disrupted Railway Traffic Situations

Railway timetables are developed to make operations robust and resilient to small delays. However, disturbances perturb the daily plan, and dispatchers need to adjust the plan to keep operations feasible and to limit delay propagation. For large infrastructure disruptions, the available railway capacity is reduced, and the timetable could become infeasible. The paper studies how to support dispatchers in the management of traffic flow during disruptions. A set of disruption resolution scenarios to manage seriously disturbed traffic conditions in large networks is investigated. For instance, in the case of track blockage, train services can be canceled, rerouted in the disrupted dispatching area, or rerouted in other areas while still with the same origin and destination. Feasible and efficient operations schedules are found quickly by an advanced decision support system for dispatching known as ROMA (railway traffic optimization by means of alternative graphs), which is based on microscopic detail and can handle large areas by decomposition. Detailed performance indicators can be computed to let dispatchers choose a specific solution, for example, by minimizing train delays and reducing passengers' discomfort. In the computational experiments, an analysis is done of a blockage on a double track line, combined with multiple entrance delays on a large railway network with heavy traffic. Several disruption resolution scenarios involving cancellation of services, rerouting, and shuttle trains are considered, and each feasible plan is evaluated in relation to travel times, frequency of services, and delay propagation.