A Study Of Optimization Of Dynamic Freight Train Diagrams Based On Market-orientation

With the quick development of the economy,the demands of individual,diversified and dynamic carriage are becoming more and more common in the market of railway freight transportation in China.However,Chinese railway freight transportation still adopts the organization-based transportation organization mode mainly based on static freight transportation plans.It is impossible to strictly implement "traveling according to the diagram",which leads to the low redemption rate of the train diagram.Therefore,the delivery time limit of the freight cannot be guaranteed,and it is difficult to meet the daily dynamic changes in the market demand for freight,and the market share is at a low level all the year round.To improve the commanding role of the train operation map,ensure and promote the efficient completion of railway freight transportation,and enhance the competitiveness of Chinese railway freight market,this paper aims to study the optimization of market-oriented dynamic planning railway freight train operation diagrams.Taking the market-oriented dynamic planning transportation organization model as the top-level design,an in-depth study on the optimization theory and method of dynamic freight train operation diagrams is carried out.The main research conducted and the results are as follows:(1)Research on the organization mode of market-oriented dynamic planning railway freight transportation.Based on analyzing the insufficiency of the current organizational transportation organization mode in China,combining the market-oriented concept with the dynamic planning transportation organization mode,the connotation and organization operation mode of the model are comprehensively explained,and a market-oriented railway freight operation system is proposed and designed,and the operation process of freight transportation under the market-oriented railway transportation organization mode is clarified.(2)This paper studies the basic theory of dynamic freight train diagram establishment under the market orientation.On the basis of analyzing the insufficiency of freight train operation diagram under the current organizational model in China,this paper comprehensively expounds the goal,significance and compilation theoretical method of dynamic freight train operation diagram based on market orientation;finally,this paper analyzes the key issues in the preparation of dynamic freight train diagrams,and proposes a progressive relationship among the three: dynamic wagon flow estimation,dynamic freight train formation planning and dynamic freight train operation diagram path selection optimization.(3)This paper studies the theoretical method of dynamic estimation of loaded and empty traffic flow in Chinese railway network.Firstly,it expounds the concept of wagon estimation and the significance of dynamic wagon estimation to the railway operation department under the new situation of freight transportation.Then,based on the in-depth analysis of the problems and deficiencies of the current wagon estimation and forecasting methods in Chinese railway system,a dynamic estimation theoretical method for the loaded and empty wagon in railway network is proposed.(4)This paper studies the preparation and optimization method of the market-oriented dynamic freight train opening plan.Based on the principle of "driving according to the flow",a flexible marshalling method of dynamic marshalling is proposed,and the calculation method of the minimum number of freight trains is determined.On this basis,a mixed integer programming model for the preparation of dynamic freight trains is constructed,and the corresponding solution strategy is designed,aiming at the minimum cost of vehicle hours,the maximum railway transportation benefit,and the minimum penalty cost of traffic flow for the reorganization of traffic flow.(5)This paper studies the optimization of freight train diagram based on dynamic path selection under the market orientation.The dynamic freight train operation diagram is the key link to realize the whole-process integrated transportation of freight and is the fundamental document to realize "traveling according to the diagram".Taking the characteristics of dynamic wagon flow as the starting point,fully considering the connection time of the wagon flow with the train at the station and the delivery time of the loaded freight,considering the quality of freight service and the satisfaction of the cargo owner,and optimizing the time consumption of each freight train on the way to the minimum.To achieve the goal,a dynamic path selection optimization model based on the basic diagram of the train operation diagram is constructed,and a solution strategy based on Binary Particle Swarm Optimization(BPSO)is designed according to the characteristics of the constructed model.