Research On Optimization Of China Railway Express Train Plans Based On Hub And Spoke Transportation Network

As an important point for the implementation of the “the Belt and Road”development strategy,the China Railway Express Train has been “fruitful” since its development.The number of transportation route has increased rapidly,the scope of operations has continued to expand,and the category of deliver goods has become increasingly abundant.Especially when the Novel Coronavirus Pneumonia spreads around the world,the China Railway Express fully demonstrated its "steel camel team" strong advantages,going against the trend,rushing to support the global fight against the epidemic,helping the economic recovery,create brand benefits,and enhancing its international influence.While the number of China Railway Express is increasing rapidly,it also highlights the shortcomings of the China Railway Express in highquality development,such as uneven distribution of supply,unstable operation frequency in some areas,long-distance overlapping of transportation routes,and malicious competition among companies operating the China Railway Express for supply.In 2016,the CHINA RAILWAY selected Urumqi as the assembly center,and began to discuss transit transportation methods to make up for the shortcomings of the "point-to-point" transportation mode.With the continuous development of the China Railway Express,Urumqi’s assembly pressure problem will follow.The optimization of the transportation plan of the China Railway Express cannot be achieved overnight.It needs continuous discussion and optimization.There is still room for optimization of the China Railway Express.This paper takes the construction of a hub-and-spoke of the China Railway Express transportation network as the basis of the physical network,and uses the dynamic transportation service network theory to optimize the China Railway Express operation plan.(1)Summarize the transportation status of the China Railway Express in terms of the number of transportation route,cities opened,channel construction,and transportation plan,and analyze the key issues that exist in the emergence stage.Based on this,the necessity of the optimization of the China Railway Express operation plan is proposed,and the theory and applicability of the research method are explained according to the main characteristics of the China Railway Express transportation network.(2)According to the research content,it is necessary to proceed from the overall situation to optimize the China Railway Express operation plan and break the premise of the cooperation barriers between companies operating the China Railway Express.On the basis of the hub-and-spoke network theory,the meaning and characteristics of the hub-and-spoke of the China Railway Express transportation network are proposed.Define the scope of the research problem through problem descriptions and model assumptions,construct a hub-and-spoke the China Railway Express network optimization model,determine the intelligent algorithm for solving,and design smallscale calculation examples.(3)On the basis of the determined physical network,analyze the possible organization of train flow and train types,construct a dynamic transportation service network,and elaborate on the meaning of the points and lines of the network.In order to simplify the solution process,a method for generating candidate sets is proposed and the influencing factors are summarized.Based on the service network,with the constraints of cargo flow balance,train continuity,marshalling capacity limitation,train service capacity limitation,transportation time limitation,etc.,and the lowest comprehensive operating cost as the optimization goal,construct the optimization model of the China Railway Express operation plan.Analyze the model and use the Yalmip toolbox to solve mixed integer programming problems.(4)Finally,the calculation examples verify that the construction method of the China Railway Express network and the optimization method of the train plan proposed in the article are indeed feasible.