Research On Optimization Algorithms Of Train Formation Plan On Railway Corridor

This paper studies the optimization of train formation plan on the railway freight corridor.The train formation plan specifies the contents of train forma-tion,that is,how to organize train flow into train flow.The train formation plan is the core of railway freight organization.Railway freight corridor is the back-bone network of railway network.Freight corridor has the characteristics of high intensity of traffic flow and easy to form congestion.Therefore,the capacity of freight corridor becomes the bottleneck restricting the capacity of the whole rail-way network.The work of this paper is to study and optimize the train formation plan of the freight corridor so as to improve the transport capacity of the freight channel and reduce the transport cost,which is of great significance to promote the transport capacity of the whole railway network and save energy consumption.At present,the train formation plan of railway freight transportation in China mainly relies on manual operation.Generally,the research is based on the whole road net-work,resulting in the problems of large scale of model,slow optimization speed of algorithm and general optimization effect.In order to solve the above prob-lems,a mathematical model is established for the optimization of single-block train formation plan and multi-group train formation plan on the freight corridor,and greedy strategy algorithm and genetic algorithm are designed to solve the model.Numerical experiments show that the optimization algorithm proposed in this paper is faster and can effectively reduce the time cost consumption in the process of freight transportation.The research contents and conclusions of this paper include:(1)This paper studies the optimization problem of single-block train forma-tion plan on railway corridor.Railway corridor is the backbone of the railway network,When applying the existing research results on train formation plan of general railway network to railway corridor,due to the characteristics of railway corridor itself and traffic flow are not fully considered in modeling,the compu-tational resources consumption is large and the optimization effect is general.In order to solve the above problems,this paper establishes an optimization model of single-block train formation plan on the railway corridor with the time of train accumulation delay and the car relaying operation as the main optimization objec-tive,and designs two iterative algorithms based on greedy strategy for the model.Numerical experiments show that,compared with the common genetic algorithm,the method adopted in this paper saves the time cost by more than 14 percent on average,and the average calculation time is reduced by about 20 percent.(2)As for the multi-block train formation plan problem,the solution result of the traditional multi-block train formation plan model is optimized on the solution result of the single-block train formation plan model.The global optimal solution of each subproblem is limited to itself,which makes it difficult to find the global optimal solution for the multi-block train model.In view of the above problems,this paper analyzes each link of the multi-block train formation planning model,and establishes the comprehensive optimization model of the multi-block train and the single-block train with the under axle traffic of each multi-group train as the constraint condition.In the comprehensive optimization model of multi-block trains and single-block train,an iterative algorithm based on greedy strategy is de-signed to solve the model.Compared with genetic algorithm,the method adopted in this paper saves 14.4 percent of the time cost and reduces the average calculation time by about 30 percent in the final comprehensive optimization model.