Research On The Complication Of Freight Train Formation Plan Based On The Comprehensive Cost

With the rapid development of railway industry in our country,China has owned the largest and highest-speed railway network with new high-speed lines building and conventional lines upgrading.Railway passenger demands in the existing lines have transferred to the high-speed lines gradually.Therefore,the freight capacity has been released to some extent.It provides the precondition for improving the level of organization of freight trains.In addition,the timeliness of railway freight transportation and the agnostic of goods have become the key factors that seriously affect the image of railway transportation enterprises and restrict the development of the market share of freight transportation.Therefore,it is an important way to improve the transportation efficiency and meet the demand of transportation market by reasonably and efficiently compiling the freight train formation plan and ensuring the rapid,economical and transparent delivery.According to the characteristics of freight transport organization in China,the thesis puts forward the technique of compiling the freight marshalling plan in stages.By introducing the importance theory of freight station based on the properties of topological structures of networks and simplifying the railway network with the technique of node system,a general model of freight marshalling plan based on Comprehensive cost is built and the corresponding algorithm on account of Lagrangian Relaxation is design to deal with the problem.Meanwhile,a case is given to validate the correctness and feasibility so that the method can provide reference for the compilation of marshalling plan.The main contents are as follows.The basic theory knowledge of the organization of formation plan based on comprehensive cost is expounded.For the through train originated from one loading point,the thesis utilizes the periodic opening method to improve the organizational efficiency of the remaining train flow after organizing daily trains.For trains in technical station,the method of node system is introduced to deal with the combination of train flows.A kind of Selection mechanism about the importance of freight stations based on the centrality theory in complex network is design.The topological structure of railway freight transportation network is constructed with the analysis of influence factors.The indexes of importance is presented and a strategy of Laplace’s centrality is put forward to describe the importance of freight station.At the same time,the algorithm of selection is realized by using MATLAB and time complexity is analyzed to measure the algorithms.A freight train planning model with comprehensive cost and an algorithm based on complex network are constructed.Starting from the point of view of complexity in marshalling plan,the thesis establishes a model of comprehensive cost based on the centrality theory in complex network firstly.The optimization goal is minimizing the comprehensive cost which includes freight cost,cost of delay time and the constraint is including the traffic organization scheme and the transport capacity.Then,Lagrange relaxation algorithm is used to simplify the model,and the relaxation problem is decomposed into the minimum cost path sub-problem and the frequency selection sub-problem.The sub-gradient algorithm is used to find the better solution of the original problem.