考虑车底运用的城轨货运专列运行图与载货方案协同优化

Urban Rail Transit Freight Train Service Planning and Shipment Allocation Considering Rolling Stock Circulation

城市轨道交通线路平峰时段客流需求相对较小、发车间隔较大,利用其富余的运输能力开展货运服务可以有效提高线路能力利用率与经济效益。本文在不调整客运列车运行图的前提下,同时采用客货共载与货运专列两种形式运输货物,研究考虑车底运用的双方向列车运行图与货物运输方案协同优化问题。以货运专列编组停站方案、时刻表、车底周转计划、货物运输方案和车站所需货物仓储容量为决策变量,考虑列车运行安全、车底周转、货物运输时效等约束,构建以提高货运净收益为目标的优化模型。通过线性化方法将原模型转化为混合整数线性规划模型,利用Gurobi软件进行求解。案例分析表明,相较于先优化列车运行计划和货物运输方案再优化车底周转计划的分步优化模型,本文方法可减少上线车底运营数3列,降低约23.6%的列车运营成本,使货运净收益提高10.3%。灵敏度分析表明,相较于客运列车,提高货运专列的货运空间和装卸载效率可以更有效地提高货运收益。

The passenger demand of an urban rail transit line is relatively small,and the departure interval is large during off peak hours.Using the spare capacity of rail transit lines to transport freight can improve line utilization and bring economic benefits.Without adjusting passenger train service planning,this paper uses passenger and special freight trains to transport freights simultaneously.The study optimizes the bilateral freight train timetable and shipment allocation while considers rolling stock utilization.A collaborative optimization model is developed with the objective of maximizing the net freight profit to determine train stopping plans,train formation,schedules,rolling stock circulation plans,shipment allocation,and freight storage capacity to be reserved at stations.The proposed method considers the constraints of train operation safety,rolling stock circulation plan,freight transportation time requirements,and so on.The model is transformed into a mixed-integer linear programming model by the linearization method and then is solved by Gurobi software.The case analysis shows that compared to the step-by-step optimization model that optimizes train service planning and shipment allocation before the rolling stock circulation plan,the proposed method can reduce the number of rolling stocks in operation by 3,reduce the operating cost of freight trains by about 23.6%,and increase the net freight profit by 10.3%.The sensitivity analysis indicates that compared with passenger trains,improving the freight space and loading/unloading efficiency of the freight trains can increase net freight profit more effectively.