Research On Optimization Of Railway Empty Car Allocation Under "Real Freight System"

The market demand of railway freight transportation is constantly changing.In order to satisfy the market demand,the China pursues the "real freight system reform".The proposed system of the real freight puts forward higher requirements for the railway freight transportation.In the case of the limited vehicle resources,it has become a hot topic for the development of railway transportation to realize the best transportation efficiency and the maximum satisfaction of the owner through the rational allocation of empty vehicles.Based on the research results at home and abroad,considering the new requirements under the real system reform,this paper studies the allocation of empty cars in China.Firstly,the paper expounds the basic theory of empty car allocation under the real freight system,and expounds the general situation of the real freight system,including the ideas and contents of the real freight system reform,the plan management under the real freight system and the significance of the reform of the freight and the real freight system.The main contents of the reform of the real freight system are to meet the demand of the cargo owners,organize the transportation on the basis of "real freight",improve the railway freight marketing system and promote the logistics development of the freight.The main content of the reform of the real freight system is to simplify the business process and change the mode of freight organization.The purpose of the reform is to enact the demand of the cargo owners.Freight plan,regulate freight charge.The freight planning organization under the condition of cargo alteration includes the annual plan,the monthly plan,the ten day plan and the daily plan.The implementation of the real freight system classifies the freight,which are mainly divided into the bulk stable materials,the bus products and the other materials.The reform of real freight system has practical significance: reducing time cost,improving transport efficiency and improving the satisfaction degree of shippers.The paper expounds the way of empty car production,the principle and method for the allocation of empty car flow organization,and the necessity of the dynamic distribution of empty cars under the new situation.Finally,it points out the effect of "real goods" on the distribution of empty car flow organization.Secondly,the space-time network method is introduced in detail.In the research of empty car allocation,there are discrete service spatiotemporal network and continuous service spatiotemporal network.Spatiotemporal network flow combines time and space,and provides new ideas and methods for solving complex dynamic flow problems.As the discrete service space network can reduce the scale of the problem,and in the process of establishing the model,the phenomenon of empty car delay is considered,so this paper uses the discrete service spatiotemporal network to construct the model and introduce the time window,in order to improve the satisfaction of the cargo owners.The model takes the maximization of operation benefit as the goal,constructs the optimization model of the single car type emptycar allocation,and then takes into account the multi vehicle phenomenon in the actual transportation,and constructs the optimization model of the multi vehicle kind of empty car allocation.Then,aiming at the empty car allocation problem of the complex road network,the paper proposes to use the harmony search algorithm to solve the model built in this paper.Firstly,the basic principle of the harmony search algorithm is introduced.Based on that,the algorithm design and the implementation process of the empty car dynamic allocation model are introduced.Finally,through the case analysis,the dynamic deployment model of the empty car is tested,and the algorithm and the results are verified,which provides valuable reference for the empty car allocation under the "real freight system".