Research And Implementation On Practical Utilization Optimization Model And Algorithm For Railway Network Freight Train Formation Plan

At present,competition in the freight transportation market is very fierce.Some traffic modes with high timeliness,such as highway transportation and air Transport,gradually take advantage of the freight transportation market,and the staple cargo volume is decreasing,resulting in the decline of the railway freight share in freight transportation market.Therefore,it is urgent to optimize the railway freight transportation organization and enhance its market competitiveness.As an important part of the railway transportation organization,freight train formation plan uniformly arranges flow organization plan of the whole railway network.It ensures that goods can be delivered to the destination through the most reasonable way,which directly influences the freight transportation cost,timeliness and functioning efficiency of facilities and equipment.This paper mainly studies the optimization method for freight train formation plan,firstly establishes an optimization model of this problem and then designs a suitable combination algorithm based on particle swarm optimization(PSO)and Lagrange relaxation to solve this model.Finally,an assistant decision system about freight train formation plan is designed to optimize freight train formation plan of the marshalling station.The main work and conclusions of this paper are as follows:(1)Optimization problem analysis.Based on the basic concept and affecting factors of freight train formation plan,the optimization objectives and constraints are defined.(2)Establishment of the optimization model.Considering the complexity of the optimization problem under the large-scale railroad network,a freight train formation plan optimization model whose objective is to minimum running time in section and waiting time in station is established to complete the effective allocation of railway resources.(3)Design and implementation of the solving algorithm.Considering the complexity of the model and applicable conditions of various algorithms,an improved combination algorithm combined with the basic idea of Particle Swarm optimization algorithm and Lagrange Relaxation algorithm is designed.In each iteration of the algorithm,Particle Swarm optimization algorithm is used to solve the blocking subproblem,and Lagrange Relaxation algorithm is used to solve the flow subproblem.In addition,the concept of mutation operator is added to avoid the local optimization of the algorithm,so as to obtain the high quality solution quickly and effectively.(4)Case study.Based on the abstract and simplified Chinese railway network and relevant data,this dissertation calculates a better railway network freight train formation plan among 15 technical stations.Through the analysis of the algorithm iterative process,the feasibility and optimization effect of the model and algorithm are verified.The results show that the method has a good practical value for the optimization of railway network freight train formation plan.(5)System implementation.Based on the proposed optimization theory of freight train formation plan optimization,a freight train formation planning management system for the marshalling station is designed to optimize freight train formation plan.The function of the system includes the management of railroad network structure,the solving of freight train formation plan,the management of freight train formation plan,the query of illegal flow and the statistical analysis of flow.The test results show that the system has good guidance for the freight train formation plan.