Energy efficiency in high speed railway traffic operation: a real-time ecodriving algorithm

The application of ecodriving strategies leads to important energy savings in high speed railway systems. Ecodriving techniques are usually offline implemented in the design of commercial services. However, efficient driving can also be online recalculated to regulate the deviations from the schedule of the train. In this paper, a dynamic multi-objective model is proposed to calculate a set of efficient drivings that are updated during the journey. Using this model it is possible to react when delays arise replacing the current driving by a faster one. The new speed profile will be energy efficient under the new conditions. The model is solved using the extension of NSGA-II for dynamic optimization problems (DNSGA-II). This algorithm is combined with a detailed simulator of the train motion. The accuracy of the simulator ensures the fulfillment of the quality restrictions in commercial services. The proposed method has been applied to a case study using real data from a Spanish high speed line. The performance of DNSGA-II solving the dynamic model has been compared with NSGA-II. Furthermore, energy savings provided by the regulation algorithm have been evaluated comparing it with the typical driving style when a delay is detected.