Research On Optimal Design Of Railway Freight Service Network

The railway transportation industry plays an important role in the development of China’s economy and society and has an important impact on the development of China’s national economy.Because it is less affected by the climate and natural environment,and the transportation cost is lower,it occupies a dominant position in the domestic bulk goods transportation market.In recent years,the proportion of bulk goods has been decreasing year by year as the transportation of finished goods has gradually taken the dominant position in the land freight market.In the face of freight demand for finished goods,the existing railway freight services have problems such as the speed,stability and poor continuity of transport,which makes most of the finished goods choose the high energy consumption transportation mode of road.Therefore,it is of practical significance to carry out research on the optimization design of railway freight service network and put forward a new model of railway freight service network for the promotion of China’s railway freight status and the development of green transportation.The research content of this paper mainly includes the following two aspects:(1)Firstly,the characteristics of freight demand are analyzed,and the factors that may affect the volume of freight demand are discussed.Then,through summarizing the operation process of railway freight transport,the cost structure of railway freight transport is analyzed.On this basis,a freight service network optimization model was established,which took the transportation cost function with delay penalty as the optimization objective,and the interval passing capacity as the constraint conditions.A genetic algorithm was designed to solve the model.The experimental data show that compared with the traditional service network model,the freight service network optimization model proposed in this paper can improve the service quality while controlling the cost.(2)In view of the uncertainty of cargo transportation demand in the actual transportation environment,this paper further adds the demand fluctuation into the design of freight service network model,and establishes the robust optimization model of freight service network by using the robust optimization method.The model focuses on the analysis of the impact of demand fluctuations on the predetermined freight service network model,quantifies the degree of deviation caused,and gives different weights to the objective function value of the original freight service network optimization model,which is combined as the objective function of the robust optimization model of freight service network.Similarly,for the robust optimization model of freight service network,this paper also designs genetic algorithm to solve.Numerical experiments show that,compared with the freight service network optimization model,the deviation degree caused by demand fluctuation to the robust optimization model of freight service network is much lower,and the final weighted comprehensive cost value is also smaller.Therefore,the robust optimization model of freight service network proposed in this paper improves the stability of the model and makes a meaningful exploration for the optimization design of railway freight service network.