Study On The Optimization Of Rail Freight Corridor Network Design Problem

Railway planning is primary and fundamental premise of the railway construction and development, and the optimization of the railway network layout play an important part in the railway planning. Along with the large-scale railway construction, the rail transportation consuming small unit energy and having less pollution is facing a golden opportunity. How to scientific plan railway development and effectively control the construction cost is an important topic that needs to be resolved and has great impaction on the development of railway industry and people survival.The defining of the rail network scale is the basis of the railway corridor layout optimization, which plays a guiding and controlling role to the railway corridor layout optimization .In this paper, we deeply studied the theories and methods mainly on railway network scale measurement and railway corridor layout optimization. The following are the main points of research and innovation of this paper:1. In the sections of railway network scale measurement, this paper proposes three measurement methods: traffic loading method based on conversion factor of the passage turnover volume, road density comparison method based on similar areas block analogy, the process of industrialization comparative method based on linkage coupling of industrial development and railway construction. One case has been analyzed by using three methods respectively and reached roughly the same result. In the foreseeable background on railway passenger line and railway freight line building, this paper detailed analyzes the total scale of the future of Railway passenger line and railway freight line respectively, forecasts the future total scale of mixed line by deduction method and transport bearer method, study the total demand for the scale of the network under different conversion factors of the volume of passenger transportation; and further study Cargo capacity-sharing rate and Equivalent mileage.2. In the section of railway corridor layout optimization, this paper firstly proposes and uses the principles and methods of four-phase method to optimize the freight rail distribution corridor. The bi-level railway network design problem based on the discrete rail network can well substitute railway single objective planning method which is mainly used on qualitative analysis but ignores network effects.3. The concept, configuration and characteristic of rail freight transportation corridors are relatively integrally discussed in the network design theory of rail freight transportation corridor, and a new thought was put forward: the railway line capacity is discretely changing under different rail corridor construction projects. Considering the existed incorporate railway network design models can not be easily resolved in practice, this paper presents the bi-level railway network design problem (BR_NDP) based on the discrete path investment decision variable. In the design of the upper layer, the attract traffic on the planned corridor and the common arc traffic of existed network are both considered in the objective function, also, the invest quota, the satisfaction degree of transportation demand, the operating cost under different layout styles and so on are all mentioned in the upper layer design model. In the design of the lower layer, the common models of traffic assignment on arc-path and node-arc are studied respectively. Considering the difference between rail flow and road flow, the traffic assignment model under the unseparated traffic flow principle and the tree-shape car flow path are discussed respectively. Combine the characteristics of the two models, we must not only make sure that OD is unseparated, but also ensure the large scale flow assignment algorithm can be carried out. A generalized shortest path traffic assignment model based on assistant factor analysis is put forward.4. In optimal multistage rail freight corridor layout model, on the basis of considering the roll planning mechanism with a cycle of five years of railway, analyzing the benefits of scale economies in the construction cost and operating cost of railway construction, an optimal multistage rail freight corridor layout model which combines the construction of passenger dedicated lines is provided based on combining the cost for investment and the construction scale of the multistage project according to a set of variable corresponding to the corridor project state. The model is proved to be well adapted to the practice application by examples.5. A case under the background of "train path diagram of western China railway network", taking Lan-Yu railway, Tai-Zhong railway and Ha-Lin railway as key decision projects is given to demonstrate the validity of the model and algorithm. Considering the impaction of induced traffic, each possible corridor constraction combination scheme is calculated and analyzed in detail.