Research On The Location Plan Of The Rail-Road Intermodal Hubs Under The "External Collection And Internal Distribution" Mode In Beijing

With the in-depth advancement of China’s supply-side structural reform and the new urbanization development,China’s industrial structure has been continuously upgraded,and urban space has continued to expand.Since the main industries of Beijing,Shanghai and other metropolises are service industries and high-end manufacturing,the proportion of transportation demand for bulk goods has decreased,and the proportion of transportation demand for high value-added goods and urban living materials has increased significantly.This has led to a continuous decrease in the volume of bulk cargo transported by railway freight stations in cities,and the objective demand for using rail freight resources to carry out urban distribution has emerged.In 2018,the State Council issued the "Three-Year Action Plan for Promoting the Adjustment of Transport Structure",which proposed to promote the rail-road intermodal transportation of urban living materials,and build a new urban distribution system under the "external collection and internal distribution,green intermodal transportation" mode.To promote the innovative development of the urban distribution mode,Beijing began to prepare for the construction of an external collection and internal distribution network of urban living materials.To make the new distribution network meet the planning requirements of "function matching,reasonable layout,intensive and efficient,green and low-carbon ",we choose to study the location plan of the rail-road intermodal hubs in the Beijing’s external collection and internal distribution network.First of all,we sorted out the supply and demand situations of Beijing’s urban freight system,and analyzed the feasibility of using rail-road intermodal transportation to carry out urban distribution under the external collection and internal distribution mode.Secondly,we analyzed the basic concepts and network hierarchy of the external collection and internal distribution mode,and proposed a two-stage method for the location plan of the rail-road intermodal hubs under the new mode.Then,we constructed a two-stage model and designed an algorithm.Finally,a case study was carried out in the background of the urban living materials transportation in the six central districts of Beijing under the new mode.The main work of this paper are as follows:(1)This paper sorted out the demand and supply situations of Beijing’s urban freight system.Based on the above supply and demand situations,the feasibility of using rail-road intermodal transportation to carry out urban distribution under the external collection and internal distribution mode was analyzed from five aspects: freight demand,infrastructure,development strategy,railway reform and green freight.This conclusion laid the foundation for the case study of the paper.(2)This paper expounded the basic concepts and other relevant contents of the external collection and internal distribution mode,and analyzed the construction and organization of the urban freight distribution network under the external collection and internal distribution mode.The railway freight station was selected as the location carrier,and a two-stage method for the location plan of the rail-road intermodal hubs under the new mode was proposed,which provided a theoretical and methodological basis for the following research.(3)A two-stage mathematical model for the location plan of the rail-road intermodal hubs was constructed.In the first stage,to determine the candidate nodes that have higher operating capacity and coordination in the intermodal transportation,we constructed an evaluation model M1 of candidate nodes based on TOPSIS.In the second stage,to determine optimal location plan under the constraints of candidate nodes,transportation network,supply and demand characteristics,etc.,we constructed a multi-product intermodal hub location model M2,and a genetic algorithm based on priority coding was designed.(4)A case study was carried out in the background of the urban living materials transportation in the six central districts of Beijing under the new mode.First,we stipulated that each end distribution outlet serves one sub-district,so 134 end distribution outlets in the six central districts of Beijing were identified,and the demand for two types of living materials in each end distribution outlet in 2020 was predicted.Then,we used the model M1,M2 and algorithm to optimize the location plan of the rail-road intermodal hubs under different freight volume conditions.Finally,according to the calculation results,the total costs and carbon emissions of the two modes were compared and analyzed.It is found that the external collection and internal distribution mode has significant advantages.