Challenge A: A more and more energy efficient railway A Model and Approaches for Synchronized Energy Saving in Timetabling

This paper proposes a mathematical approach that can increase energy saving in timetables. The energy-efficient timetabling method, we use, maintains the planned traveling time between stations, but coordinates the train departure times at the starting station from current timetable.We formulate this problem as a multi-criteria mixed integer programming to minimize the peak energy and simultaneously to maximize the re-usage of regenerative energy.We also apply our model to the instance obtained from the real-world data of the Korea Metropolitan Subway. From the experiments, we can see an improvement of not only approximately 40% in peak energy, but also 5% in re-usage of regenerative energy.