Research On Optimization Of Transportation Organization For Railway Express Freight Based On Shipper Demands

To meet the demands of shippers is the basic task of railway freight transportation, especially for express freight, which has the characteristics of small batch, excellent timeliness and high value, and more attention should be paid to diversified transportation service demands of shippers. In recent years, the infrastructure construction and informatization construction of Chinese railway have achieved remarkable results, and the level of railway technical equipment and the capacity in points and lines have been improved greatly, which provided favorable conditions for carrying out the transportation organization of railway express freight based on shipper demands. Meanwhile, the implementing of reform railway freight transportation organization promotes the change from production to service. Consequently, research on the theories and methods of railway express freight transportation organization has important significance to accelerate the development of railway express freight and decrease the entire logistics cost of express freight.In this dissertation, the concepts of express freight, railway express freight, railway express freight transportation and express freight train are defined firstly. Then, influencing factors and primary contents of railway express freight transportation organization are discussed in detail. We put forward the organization methods of railway express freight taking railway freight marketing center as the responsibility principal part to deal with express freight transport business, so that it is propitious to realize the integrated organization of freight source and freight flow, and improve the transport service levels for express freight.Secondly, the shipper demands of express freight are analyzed detailedly, and then, the model and algorithm for the choice of railway express freight transport products are designed. For different kinds of shippers have different priority on choosing freight transport products, besides, railway express freight transport products often have capacity limitations. So we classified the shippers of railway express freight at first, then, we constructed the optimization model of express freight products choice for multi demands and with capacity constraints. Taking the model as a basis, freight transport product choice model of multi-demands without capacity constraints and the model of single demand are established, in addition, exact solution and Genetic Algorithm are designed according to the characteristics of the problems. These models and algorithms can not only provide references for shippers to choose freight transport products, but also provide decision-making basis for freight transportation enterprises to plan and improve their products and organization methods.The operation plan of express freight trains is the key to transportation organization of railway express freight, as well as critical response to shipper demands. We research the operation plan optimization of express freight trains based on shipper demands, and establish optimization models for express freight trains respectively considering through organization mode and the organization mode with throwing and connecting operation. In view of the sparseness of the railway express freight transport network, the proposed models are path-based, so that the complexity of constructing and solving the models can be lowered. Based on synthetically considering shipper demands and railway operation, we propose multi-objective programming models for the operation plan of express freight trains, which take maximum shipper demands and minimum transport cost of shippers as optimization objectives to realize the distribution of car flows to candidate paths. In these models, the number of marshalling cars for express freight train is configured as a decision variable rather than a constant, so that the characteristics of express freight trains can be better satisfied. Then, depending on the characteristic of the model, solving methods on the basis of the Genetic Algorithm are designed. Finally, a numerical case is applied to test the feasibility of the models and the algorithms.Considering that shippers have more and more initiative on selecting railway express freight transport products, and also have more ways to deal with freight transport business, so we suggest the organization of freight source be more precise. By analyzing the problems existing in the organization of railway express freight source, we put forward relative strategies and methods to defeat them. Furthermore, two models for the organization of the express freight source are proposed, one is under the condition of shippers choosing trains, the other one is under the condition of shippers doing not choose trains, and corresponding heuristic algorithms are designed for both models.The dissertation systematically researches the theory and method of freight source organization and trains operation for railway express freight from the aspect of meeting shipper demands, which are profitable supplement for railway freight transportation organization system. It also can provide a reference for the practice of railway express freight transportation organization.