Research On Collaborative Optimization Of Multilayer Express Freight Train

The railway express freight train scheduling is an important part of the railway express freight operation organization.whether the operation scheme is good or bad will directly affect the subsequent operation system and the operation scheme of railway transportation.A good operation scheme to improve transport efficiency and enhance railway transportation brand has a very important significance.On the basis of introducing the structure and characteristics of typical express products at home and abroad,this paper analyzes the problems existing in the operation mode of express trains in china.At the same time,introducing the contents and characteristics of fast freight demand forecasting,analyzing detailed the factors affecting the transportation demand,based on the cumulative prospect theory and stochastic optimization,a transportation demand forecasting model is established,which provides the basis for the model of express freight operation.In order to reflect the importance of nodes in the model,this paper combines the characteristics of the hub and spoke network and layers the fast freight network in the part of the establishment of the operation scheme model.At the same time in order to ensure the robustness of the operation plan and ensure smooth transit of goods,the transit wait time function is reconstructed based on the flexible optimization theory for collaborative train transit problems.Then,to maximize the transportation efficiency and minimize the amount of time spent in the transportation of all goods,the optimal design model of operation plan is established considering the constraints of the traffic flow,the train carrying capacity constraints,and the passage capacity constraints.According to the characteristics of the model,a hybrid heuristic algorithm is used to solve the model.According to the above model and algorithm,an example is given,and then the influence of the buffer time and the number of trains on the total transportation time and gross profit is analyzed.The results show that selecting the appropriate buffer time and the numbers of trains are beneficial to increase the profit and reduce the transportation time.