Research On Optimization Of High-speed Railway Capacity Under The Condition Of Large Number Of Cross-Line Trains

With the growth of China high-speed railway network(CHSN)and the increasing demand of the direct transport service,which are always long-distances,the proportion of cross-line trains in a train line plan starts soaring.However,a high rate of cross-line trains will lead an intense capacity utilization of CHSN.Jinghu(Beijing-Shanghai)Line,the same situation as other lines in other railway lines in the East and Middle part of China,is a typical instance.On the basis of considering the characteristics of cross-line trains,this thesis puts forward the method of adjusting the operation scheme of high-speed railway trains,which refer to the suitable time window and the time-space diagram schedule priority of cross-line trains.The research mainly include six aspects:(1)Analysis on the key factors of the high-speed railway transportation organizationThis thesis analyzes the advantages and disadvantages of the modes of cross-line trains and non-cross-line trains in detail,discusses the main considerations of high-speed railway train operation diagram based on the perspective of capacity utilization,and excavates the potential to improve the capacity as the basis points for adjusting the highspeed railway train operation scheme.(2)Identify two major ways to realize capacity optimizationThat is,compress the train tracking intervals and adjust the operation scheme of high-speed railway trains.When analyzing the compression of train tracking intervals,the influencing factors are divided into four categories and fourteen sub categories.Four main ways of compressing the train tracking intervals are proposed,and the influencing factors are reclassified according to the feasibility.When analyzing the adjustment of railway train operation scheme,the concepts of time interval and time occupation are introduced to measure the capacity utilization,and as the direction of adjustment for the operation scheme of high-speed railway trains.(3)The introduction of the time-window calculation model for cross-line trainsA suitable time-window calculation model is introduced which could satisfies the requirements of passengers convenience,maintenance,and improve capability utilization.The calculation model is designed based on the headways among train services and it belongs to integer programming mode.And the solution algorithm is annealing algorithm.Overall,the results of this part are the inputs of adjustment model designed for the following part.(4)The introduction of the adjustment model of high-speed railway train line plan based on capacity utilization improvementThis model considers the following factors: the relationships between cross-line trains and non-cross-line trains,and the stopping pattern of a high-speed train line plan.The objective function is designed from the perspective of the time occupation of a timespace diagram,which is defined as the capacity utilization.CPLEX is used to solve the model,so as to obtain an adjusted high-speed railway train line plan.(5)The introduction of a capacity optimization evaluation frameworkThe evaluation framework includes the optimization rate of high-speed railway capacity,the time occupation rate,the train encryption rate and additional time rate.The method of increasing train lines is used to calculate the section capacity utilization and the basic process is described.(6)A case study and the verification of the modelThe case study takes the section from Jinghu high-speed railway line,which starts from Nanjing South Station to Shanghai Hongqiao station,as the research subject.Related calculations and optimizations are finished and a comparative analysis is given.The results show that the capacity utilization improvement can be achieved.The level of the utilization improvements can deliver a similar level as simply compressing the headways among train services,which means that corresponding tasks can be avoided or simplified if taking compressing headways is the only choice.At the same time,our model provides an effective way to improve the quality and efficiency of time-space diagram schedule.Finally,some suggestions are put forward.This thesis contains 20 Figures,20 Tables,and 54 References.