文摘
Nowadays, energy efficiency is a key requirement for railway systems in order to reduce operating costs. One of the main solutions for implementing energy efficiency is the optimization of train speed profiles to minimize tractive energy consumption. From a transportation systems point of view, the definition of optimized speed profiles should consider their possible impact on rail traffic flows, in order to evaluate their feasibility. To do so, an innovative optimization framework for the definition and the evaluation of energy efficient speed profiles, based on supply design modelling, is proposed. The framework operates on two levels: the first level generates energy efficient speed profiles with respect to timetable constraints, infrastructure characteristics and rolling stock features, and the second simulates these speed profiles on the rail network within the specific rail traffic conditions. Through this new integrated view, the evaluation of the proposed optimal speed profiles can fully take into account the operational requirements of the services, such as trains scheduling, absence of or small allowance for delays and respect for buffer times for passenger transfer at connecting stations. A numerical example based on a calibrated simulation model of the suburban S-Bahn S9 line that operates in the Canton of Zurich shows how energy efficient speed profiles can be defined considering the rail traffic influences, thus increasing the quality of the solutions.