Optimization For Train Routing Scheme In Urban Rail Transit Network

With the construction of urban rail transit,it has gradually evolved from a single line to rail transit networks.During the extension of existing lines and the construction of new lines,passenger flow distribution characteristics of rail lines have changed.If train operation plan is not adjusted in time,it will result in a mismatch between the transportation capacity and the passenger demand,and affect the transport efficiency of the entire rail transit network.Therefore,according to the passenger flow characteristics of rail lines in different function orientation,this paper proposes alternative train routing schemes and establishes an optimization model for train routing scheme in urban rail transit network.These will provide a feasible operational method of rail transit networks.The main research contents are as follows:(1)Through extracting and processing the passenger information of AFC system,the OD traffic flow between each rail station is obtained.This paper analyzes the passenger flow distribution characteristics of rail transit networks and summarizes their general rules under different functional orientation.Also,the importance of rail transit lines are calculated,it can set the priority for rail transit lines when optimizing multiple lines at the same time.(2)This paper formulates the rules for identifing bottlenecks of rail transit networks.Then,full-length and short-turn routing train operational theory is used to match transport capacity and passenger damend under different functions orientation of rail transit lines.Taking Beijing rail transit as an example to identify the bottleneck section,targeted train routing optimization schemes are proposed for the rail lines whose transport capacity and passenger demand are unmatched.(3)This paper gives the calculation method of rail transit networks' passenger waiting time under full-length and short-turn routing.When calculating the passenger waiting time,the transfer passenger waiting time and passenger detention time are considered.Based on the goal of minimum passenger time cost and minimum operating cost,an optimization model for train routing scheme in urban rail transit network is established.(4)The optimization model are solved by multi-objective optimization genetic algorithm NSGA-II,and the NSGA-II algorithm are designed according to the model.In the solution process,multiple rail transit lines are optimized at the same time.By using the NSGA-II algorithm,a Pareto optimal solution is output,operators can select different optimization schemes according to the operation cost.(5)In this paper,6 rail lines under different functional orientation in Beijing rail transit are used as examples,and Matlab is used to solve the model.After multi-program comparison,a trade-off solution is output The optimization results are analyzed by evaluation indicators,and the results show that the optimization scheme works well.Compared with the single train routing scheme,the full-length and short-turn train routing scheme can reduce transport capacity waste and improve transportation effciency.The feasibility and applicability of the optimization model and multi-objective genetic algorithm in this paper are verified.