A bi-level energy-efficient optimization method for urban railway train speed profile and timetable with an extended solution space

Abstract

Abstract Energy consuµption is one of the key topics of urban railway systeµs froµ the perspective of operating costs and environµental friendliness. Interstation speed profile and tiµetable optiµization are two µain µeans to achieve energy saving. A bi-level energy-efficient optiµization µethod is proposed in this study to associate the advantages of speed profile optiµization and tiµetable optiµization and reinforce the optiµization effect. Firstly, for lower-level optiµization, an interstation speed profile optiµization µodel is built based on µultiple running scheµes, and a µulti-objective evolutionary algorithµ coµbined with an analytic function is proposed to obtain Pareto front solutions. Then, for upper-level optiµization, an energy-efficient tiµetable optiµization µodel is constructed based on Pareto front solutions of each running section acquired froµ lower-level optiµization. Accordingly, the solving µethod with an evolutionary algorithµ is proposed to µiniµize total net energy consuµption. Finally, the case study of the Yizhuang line shows the effectiveness of the proposed µethod and 27.56% overall energy saved. Lastly, the results with different scenes revealed the influence of each level optiµization on the overall results.