Study On The Optimization Of Urban Rail Transit Train Operation Organization Under Networking Conditions

China’s urban rail transit has been growing rapidly in recent years. Continuous construction of new lines has improved the rail transit network and highlighted networking characters.Networking of urban rail transit has brought many new features to its operation. The existing operation theory for small-scale urban rail transit network with single-structure cannot meet the objective demand under the situation of networking operation. The optimization of urban rail transit train operation organization under networking conditions is a new field, which has important practical and theoretical significance. This paper attempts to explore in this field and the following sections are included in its work:(1) On the basis of fully analysis of the characters of urban rail transit network, this paper focuses on the rail lines and transfer nodes, and puts forward a method to determine their importance degree.(2) This paper analyzes the characters of network passenger flow, and then studies the main problem of train operation organization under networking conditions, including train marshaling scheme and train routing chosen. The optimization principles of train operation organization within single line under networking conditions are determined. With targets of matching actual passenger flow volume, an optimization model of train marshalling and train operating interval is built, which is solved by a fuzzy mathematical programming approach.(3) The coordination of train operation organization among several lines is studied, using the method of overall parallel move of train path by a certain period of time. Firstly, passengers’ transfer process is studied and Weibull function is used to describe the walking time distribution. Secondly, the model of minimizing transfer waiting time is formulated to coordinate train operation between two lines, and a solution of the model has been achieved by derivation of the objective function. Then the coordination of multi-line train operation has been analyzed and a corresponding hierarchical coordination algorithm is given. Finally, a case study of a simple network consists of several lines from Beijing subway is carried out. The results suggest that Weibull function could well describe transfer walking time distribution; the method of overall parallel move of train path by a certain period of time could effectively optimize reasonable convergence of various trains in different lines in the transfer node; the model and its solution proposed by the paper are effective and could be used in practice.