Optimization Of Railway Express Freight Trains Operating Plan In China Under The New Normal

As China's economic develops into the New Normal,social industrial structure has also undergone great adjustments.The government launched a new strategy to focus on dissolving over-capacity of production and upgrading the industrial transformation.This has resulted in a great impact on the railway transportation,which is dominated by bulk cargo transportation.Because of the rapid reduction of transport demand and the competitive pressures of other modes of transport,express transport is a major trend for modern railway development to adapt to modern logistics market.And the operating plan is the guiding document of the railway sector,whether it is reasonable or not directly affects the transport efficiency and service level.Thus,the study on the operating plan of express train is of great significance to improve the occupancy rate of railway in the express market and utilize the railway transportation capacity rationally.This paper studies several related problems in the optimization design of railway freight express train under this background.1.The status of organization of the current express freight train in China is summarized.Through the statistics of the operating plan of express freight train published by China Railway Service Center,the organizational processes of express cargo transportation,the product system of express freight train,and the main characteristics of various express trains are analyzed systematically,and the conclusion is drawn that there are some problems such as lack of market competitiveness,low fulfillment rate of train,insufficient product development strategy and insufficient optimization of operating plan in China's express freight train.2.The compliation method of the operating plan of the express freight train under the condition of stabilizing direct trains preferentially is studied.Aiming at the high timeliness of express freight demand,this paper puts forward a method of fixing some high quality and stable cargo flow on direct train.In addition,Four factors,namely the operation mode of combining the direct train with scheduled transit train,flexible car grouping,multi-level service and shipper's maximum allowable delivery time,are taken into account while the rest of the cargo flow is compilated into the operating plan.Therefore a more feasible operation plan is get ultimately.3.An optimization model of the express freight train operating plan based on node partition method is built.Each node is parted into the arrival node and the departure node,and the joint arc is added between the nodes to get the railway freight express train transportation service network.In this way,the optimization problem of railway freight express train can be understood as adding the joint arc in the network afterparting,which is translated into a special kind of network design problem.The k Shortest Paths algorithm is used to allocate the cargo flows to the transportation network.On this basis,the operating plan of the express freight train is determined.Finally,the commercial software LINGO11 is used to solve the model.The example shows that the given model and the solution strategy can get the global optimal solution of the problem in a short time.