Research On Optimization Of Railway Container Turnover Utilization

As a modern and advanced mode of transportation,container transportation has the advantages of high efficiency,convenience,safety,reliability,environmental protection and economy.The development of railway container transportation is conducive to expanding the effective supply of railway,which is of great significance for giving full play to the advantages of railway and reducing the logistics cost of the whole society.However,the widespread problem of empty container allocation leads to the slow turnover of railway containers in our country,which causes great difficulties for efficient container transportation organization,and also causes great waste of human and material resources,which is not conducive to the development of railway container transportation.At present,China’s railway container transportation organization is to separate the heavy container transportation from the empty container allocation,and carry out daily empty container scheduling according to the determined or predicted container transportation demand in the next few days.Nevertheless,empty container allocation and heavy container transportation are interrelated.Considering both of them,the optimization of container turnover can reduce empty container allocation and increase heavy container transportation,so as to improve the efficiency of transportation enterprises.The main contents of this paper can be summarized as follows:Firstly,the paper introduces the development process and current situation of railway container transportation,combs the process of railway container turnover application,expounds the relationship between heavy container transportation and empty container allocation,and puts forward the idea of optimization of railway container turnover application.Aiming at the problem of empty container allocation,this paper analyzes the current situation of supply and demand of empty containers and the command mode of empty container allocation,probes into the causes of empty container allocation,and puts forward corresponding measures to reduce empty container allocation.Secondly,the optimization model of railway container turnover is established.In this paper,the optimization problem of container turnover operation is transformed into a multi commodity network flow problem including freight flow and container flow,and the basic assumptions of the model are put forward.Finally,taking the flow distribution of freight flow and container flow on the empty container allocation arc of heavy container transportation arc as the decision variables,and taking the maximization of railway container transportation revenue as the objective function,a0-1 model based on discrete time-space network is established Integer programming model.Thirdly,the Lagrangian dual problem is constructed by relaxing the constraints that make the model difficult to solve.The original problem is transformed into independent cargo flow subproblem and box flow subproblem.The strategy of solving the dual problem and the method of updating Lagrangian multiplier are determined.The Lagrangian heuristic algorithm for obtaining feasible solution and the overall framework of Lagrangian relaxation algorithm are designed.Finally,a small-scale example and a case based on local road network are designed to verify the model and algorithm.In a small-scale example,the number of empty containers and freight demand at the initial time of each station are adjusted,and the sensitivity analysis of the solution results and efficiency is carried out,which verifies the correctness of the model.At the same time,it also proves that the Lagrange relaxation algorithm designed in this paper has higher solution efficiency than the commercial solver CPLEX.Then a large-scale case study is carried out on the local road network in China,and the results show that the model and algorithm are also effective and practical in large-scale cases.