Research On Optimization Method Of Flexible Route Setting In Urban Rail Transit

The urban rail transit has been widely considered as the most important component in urban transport infrastructures and the projetcs of the urban rail transit construction has been promoted continuously,which leads to the extension of existing lines and the opening of ultra long lines.The temporal and spatial characteristics of passenger flow show the trend of the imbalance because of the regional differences in the ultra long lines of the urban rail transit.If the single full-length route is adopted in every line,the section transportation capacity will be wasted.Therefore,in order to reduce the operation cost and improve the transportation efficiency,the enterprises should choose more reasonable service routes with the consideration the network effect and the unbalanced distribution of passenger flow in time and spaceFirstly,the concept and the selection principle of the route change point are put forward when the different types of service route forms’ characteristics are summarized as well.Influence factors of route change point selection are analyzed systematically from four aspects,the temporal and spatial characteristics of passenger flow,passenger demand,operation requirement,and supply ability.It provides the theoretical basis to establish the optimization model of urban rail transit route change point selection.Secondly,the urban rail transit network is processed abstractly and the information of the stations and lines are converted into data that conforms to the progranmming operation.Besides,by analyzing the data obtained by the automatic fare collection system,the OD table is generated.Then the effective path is defined and the search algorithm based on transfer times is given.To solve the problem of the passenger flow assignment in the effective path,a Logit-based model is built.In the end,the results of passenger flow distribution are analyzed,which provides the important data for the whole paper.Thirdly,the necessity of multiple service routes is analyzed when the line is unbalanced and the vehicle is insufficient.In the design stage,the selection range of service routes should be determined by the set of sections with high passenger flow characteristics.In the operation stage,it should be determined by the operation conditions.With the purpose of reducing the serviceable vehicles,an optimization model for the selection of service routes is established considering the passenger demand,the capacity of the line,the convenience of passenger,the number of servie routes and so on.In addition,relevant indicators are selected to evaluate the operation effect of the model.Finally,taking the Line 2 in the Chengdu Metro as the examplet,this paper analyzes the passenger flow characteristics of the line in the morning and peak hours in the beginning.Then,,the service routes are determined as Xipu,Chadianzi Bus Terminal Station,Chengdu Academy of Governance and Longquanyi through the established model.The result shows that 13 and 7 trains are saved,the running kilometers of trains are reduced by 25.52% and18.48%,and the transportation efficiency is improved by 41.81% and 28.03% compared with the actual service route and the single full-length route,which verifies the effectiveness of the model.