Research On Dynamic Random Distribution Of Railway Empty Wagons

In recent years,with the rapid development of my country’s economy and the continuous changes in the industrial structure,higher requirements have been put forward for the rational use of empty car resources in the process of railway freight transportation.The deployment of empty wagons is an important part of railway freight.It not only determines whether the cargo operations at the station can be carried out smoothly,but also affects the level of railway freight services.However,due to the influence of many subjective and objective factors,it is particularly difficult to formulate a reasonable and efficient empty vehicle allocation plan.Therefore,this issue is always an important subject worthy of in-depth study.This paper mainly studies the problem of railway empty wagon allocation from two aspects: dynamic and random.The dynamic allocation process is mainly realized by constructing a time-space network.Randomness is realized by transforming uncertain factors into random variables in the railway freight network.From the perspective of the enterprise,the objective function is constructed for the minimum transportation cost and other expenses.At the same time,the time reliability of the arrival of empty vehicles is used to guarantee the interests of freighters,a model is constructed for the coordination and optimization of costs and timeliness.The main study of this paper is as follows:(1)Determine the dynamic allocation of empty railway cars in the environmentWhen constructing a dynamic space-time network,this paper discretizes the continuous transportation process in different time periods,and then analyzes the changes in the supply and demand of empty wagons in each stage,and at the same time considers the time reliability of empty vehicle deployment,and based on cost and timeliness establishes a coordination and optimized model.The model takes the minimum total transportation cost,the minimum cost of empty wagons inventory and delay loss,the minimum vehicle type substitution cost,and the maximum reliability of the total empty vehicle arrival time as the optimization objectives.It considers dynamic demand constraints,supply quantity constraints,and paths of transportation capacity constraints in each time period.(2)Dynamic deployment of empty railway cars under random environmentBased on the modeling of the dynamic allocation of empty vehicles in a certain environment,considering the supply and demand of empty vehicles and the randomness of the transportation capacity of the road section,a chance-constrained programming model is established for dynamic empty vehicle allocation in a random environment,finally it is transformed into deterministic and equal model.(3)Algorithm design and analysis of calculation examplesWhen designing an improved harmony search algorithm,a rolling time-domain strategy is adopted to transform the dynamics in the transportation process,so that the actual operation is consistent with the information changed in each period,the algorithm parameters are designed and the algorithm flow is introduced in detail.C++ Programming enables algorithms to be realized.In order to verify the effectiveness of the model and the solution algorithm,3empty car supply stations and 4 empty car demand stations were designed for the dynamic allocation of empty cars in certain and random environments.The algorithm was solved under different parameters.