Research On Optimization Of Integrated Railway Wagon Flow And Train Path Problem Based On Freight Transit Period

The railway is one of the main means of transportation in the comprehensive transportation system and plays a vital role in the social and economic development of our country.With the release of the common line’s capacity,it provides a strong guarantee for the reform of China’s railway freight transportation.However,the fierce competition between the various modes of transportation in the current freight market and the high requirements of goods owners for the punctuality and timeliness of transportation services have also brought great challenges to railway freight transportation.Therefore,it is extremely important to optimize the railway freight transportation organization mode and study on the integrated wagon flow and train path problem.It can not only control the whole transportation status of the goods,calculate the delivery time of the goods,guarantee the transit period,but also optimize the design of the transportation service network and reduce the total delivery time to improve service quality.This paper first reviews the research status at home and abroad,points out the shortcomings of the existing research,clarifies the research content and direction of the optimization problem of integrated wagon flow and train path,then analyzes the theory of railway freight transportation organization in China,and constructs the optimization model of integrated railway wagon flow and train path problem.The Lagrangian relaxation algorithm is designed to solve the problem,and the effectiveness of the algorithm is verified by a small case.Finally,the road network and data of Shenyang Railway Bureau are taken as an example to prove the practical application value of the paper.The main work and research contents are as follows:(1)Review the research status at home and abroad from two aspects:the delivery time of goods and the design of transportation service network.After clarifying the existing research,it is decided to estimate the delivery time of the goods from the perspective of the whole process of cargo transportation,and use the time-discretized space-time network to describe the two-dimensional properties in time and space of the wagon flow,and optimize the design of the transportation service network to adapt to the fluctuation of wagon flow and ensure the transit period.(2)Research on the theory of railway freight transportation organization in China,clarify the freight planning system,and divide the delivery process of goods into the initial and final delivery operation process,the technical station transfer operation process and the travel process.Then analyze the cargo operation time of each process,and improve the organization transportation mode at the current stage,and use it in combination with the planning organization mode.(3)Construct the optimization model of integrated railway wagon flow and train path problem based on transit period.The minimum total delivery time of the railway network is taken as the objective function.The time-discretized space-time network is used for modeling,and the space-time network is improved and optimized to simplify the model complexity.Then the Lagrangian relaxation algorithm is designed to solve the upper and lower bounds of the model,and the effectiveness of the algorithm is verified by a small case.(4)Take the network and data of China Railway Shenyang Group for case analysis,collect data and set parameters,then construct an improved time-discretized space-time network,and solving the goods transfer plan and transportation service network design plan,the feasibility of the result and,the optimization effect is analyzed to show the practical value of the paper.