Research On Dynamic Service Network Design With The Balance-constraint Of Resources For China Railway Express

Nowadays,the trade between China and Europe has been developed rapidly,and the“One Belt One Road” initiative has also achieved continuous progress.In this kind of environment,the total volume of cargo transportation between China and countries along the “One Belt One Road” is also increasing at a high speed.The scale of the China Railway Express is pushed to growing.However,in the process of continuous growth,due to the unbalance of transportation resources(such as container and vehicle)of some station and overload of many railway ports(such as Erenhot,Alashankou,Manzhouli,etc.),the cargo stays at the railway port for too long,resulting in that the delivery time limit of the China Railway Express is failure to be guaranteed.So the transportation resources of China Railway Express to be reasonable planned is in an urgent need.In order to make sure that the delivery deadline will be guaranteed while the total operating cost of the train operator to be minimized,we construct a model in which the freight transportation of China Railway Express is took as the research object,the time dimension is going to be added,and optimization of transportation resources is comprehensively considered as the condition of model.The thesis work is carried out from the following aspects:1.The existing domestic and foreign literature on container transportation,China Railway Express and service network design research is summarized,and then the relevant theories of railway container transportation and service network design to be introduced.Based on the analyzes of the current situation of China Railway Express,the relevant factors affecting the design of the China Railway Express service network design and the principles of the service network design,finally the main content of the dynamic service network design of the China Railway Express is proposed.2.The cargo transportation problems of China Railway Express is going to described.Based on research of the existing transportation service network design of China Railway Express,the time dimension will be added to construct the time-space network of the transportation of China Railway Express,including the time-space network of the use of vehicles and the time-space network of cargo route and container route.On this basis,in order to make sure that each station has enough transportation resources to complete the corresponding transportation tasks in the next cycle,the dynamic service network design model of China Railway Express considering the coordination of transportation resources is going to be established.In which the total cost to be minimized is took as the objective function,and the constraints of vehicle balance,time-space route selection,and container balance to be considered.3.According to the NP-Hard characteristics of the model,the solving algorithm is designed based on the Lagrangian relaxation algorithm,the complex constraints in the model are absorbed into the objective function through Lagrangian multipliers,thereby the original problem can be relaxed.On this basis,the original problem is decomposed into the sub-problems which are relatively simple,further reducing the difficulty of solving the model.And then part lines of the China Railway Express network is selected to construct physical network of test case,cargo data on the network is simulated,and then the test case of different scales is going to be solved by LR algorithm.Meanwhile,the solution results of test cases solved by LR algorithm is going to be compared to the result of GUROBI to verify the efficiency of the algorithm.