A Study On The Optimization Of Marshalling Stations' Spatial Configuration In Northwestern China

With the deepening of China railroad's freight reform,China railroad industry has been transforming its traditional planning mode to a market-oriented one.At the same time,the density of the high-speed rail network is greatly improved,so that the freight transportation capacity of the existing lines has been released to a great extent.Under the background of freight reform and railroad network expansion,the workload of the marshalling station will inevitably change in the next decades.This thesis is to explore the spatial configuration of the marshalling stations in the northwest region of China,based on the long-term railroad network in the region.The organization of car flow is an important factor for the marshalling station when it comes to the configuration optimization.The change of one marshalling station's configuration will directly affect the train connection service plan,which will also have a significant impact on other stations in the railroad network.Therefore,when optimizing the configuration of marshalling stations,we should not focus on only one station.It is necessary to proceed from the perspective of the railroad network as a whole and combine the car flow reclassification scheme to carry out collaborative optimization.On the basis of the research on marshalling stations' spatial configuration from home and abroad,and the development status as well as the long-term development plan of China railroad,this thesis combines the theories of car flow organization and the complex networks to analyze and optimize the spatial configuration of marshalling stations in the northwestern region of China.The main research contents of this article include the following parts:1.Theoretically analyze the factors that affect the spatial configuration of marshalling stations and the principles for determining candidate marshalling stations.Then,based on practical problems,we analyze the railroad network and freight structure in the northwestern region.The focus is on the railroad network structure and the current configuration of several important marshalling stations,as well as the structure of cargo flow and the car flow.2.Based on the optimization method of car flow organization,the configuration of the marshalling stations of railroad network in northwestern China is studied and analyzed.We use the optimization model established for train connecting service problem,whose objective is minimizing the sum of the marshalling plan's accumulation cost and reclassification cost,without consideration of the capacity constraint.We apply the simulated annealing algorithm to obtain the optimal plan for the train formation plan in the Northwest China,calculate the workload of each station,and get the conclusion that some stations' capacity is close to saturation.At last,a marshalling stations'configuration optimization plan is proposed.3.Based on the theory of the complex networks,the spatial configuration of marshalling stations in China's northwestern region is analyzed and optimized.We separately construct the railroad physical network and the railroad service network in the northwest region.For the physical network,the degrees,in-between and vulnerability indices of each station in the railroad network are analyzed.For the service network,the railroad network's indicators such as the degree of access,access strength,and intensity correlation of each Fulcrum are analyzed.The ranking of each station based on the importance of each index is obtained.Finally,a weighted configuration proposal of the marshalling stations based on the complex network theory is obtained.4.A comparative analysis of two configuration proposals for marshalling stations,based on the train connection service plan and the complex network theory respectively,is conducted.Finally,a comprehensive proposal for the marshalling stations'establishment and improvement in the northwestern region is obtained.