Research On Optimization Of Market-oriented Intercity Railway Line Planning Under Variable Marshalling EMU

Market-oriented operation mode is the future development trend of intercity railway operation organization,which emphasizes the market dynamic passenger flow demand as the guide,strives for a high degree of consistency between the allocation of transport resources and passenger travel demand,and provides better services for passengers while ensuring the income of railway departments.As the first step of "group flow on line",railway line planning determines the spatial structure of intercity railway transportation products,which is an important basis for subsequent transportation product design.Therefore,in order to better meet the transportation production demand of marketoriented operation mode and realize the market-oriented operation of intercity railway,it is necessary to further explore and closely follow the passenger travel demand in the process of optimizing railway line planning.In this paper,based on the fine division of passenger demand periods,applying variable marshalling EMU,intercity railway line planning was optimized and adjusted in different time periods and directions,hoping to obtain a market-oriented railway line planning that highly meets the market demand.The main research contents are as follows:(1)The related theories of market-oriented railway line planning were combed.On the basis of market-oriented connotation,the connotation and characteristics of marketoriented transportation organization were clarified;the factors and preparation principles of railway line planning were summarized;combined with the marshalling characteristics of variable marshalling EMU,the necessity and feasibility of applying variable marshalling EMU to market-oriented transportation organization optimization were demonstrated.(2)The division method of passenger flow demand period was put forward.Taking several practical lines as examples,the structural characteristics and fluctuation characteristics of intercity railway passenger flow demand were analyzed,and the time division method of intercity railway time-varying passenger flow demand was proposed.Based on the division results,the upper limit constraints of service frequency under different peak types were determined.(3)The optimization model of market-oriented railway line planning was constructed.Guided by passenger flow demand in different periods,applying variable marshalling EMU,aiming at minimizing railway operation cost and passenger travel time cost,considering the constraints of capacity resource allocation and the upper limit constraints of train service frequency determined according to the results of passenger flow period division,an integer programming model was constructed,intercity railway line planning was optimized and adjusted in different time periods and directions by using this model.(4)According to the characteristics of the model,a particle swarm optimization heuristic algorithm was designed.Based on Particle Swarm Optimization(PSO),a twostage optimization process was proposed by analyzing the coupling relationship between different variables of the model,in which railway line planning was solved first,and then the passenger flow route selection was solved according to railway line planning.Making full use of the structural characteristics of the model,the difficulty of solving was reduced.(5)Taking the actual line as an example,railway line planning was optimized in two situations: sufficient resources and tight resources.The results show that when the resources are sufficient,the obtained line planning can realize the market-oriented operation of intercity railway,and compared with the fixed marshalling,the railway operation cost is reduced by 6.84%,the passenger travel cost is reduced by 2.54%,the train departure frequency is increased by 46.63%,and the train load factor is optimized by 13.39%;When resources are tight,the train operation scheme also has the characteristics of marketization,and compared with the fixed marshalling,the number of passengers stranded can be reduced by 40.82%,and there is also a certain degree of optimization in other indicators.The rationality of the optimization method is verified,which shows that the research results can provide reference for market-oriented operation organization of intercity railway.