Network-based Traffic Organization With Implementation For Urban Rail Transit Operations

In the construction process of urban rail transit system, a network with strong relevance among lines gradually comes into being from only a few lines having poor relation, and the applicable organization modes, implementation methods and technologies of network operations become more complex.The organization modes and implementation technologies of urban rail transit network operation, such as multi-line transfer, joint operation, multi-routing operation, express/slow train operation, train reformation, depot sharing, income assignment, have been discussed in varying degrees, some of which have been deeply studied. However, there are few studies on the comprehensive application of these methods and the corresponding effects like carrying capacity and operating efficiency. Therefore, contributions of several network geometric forms to transfer capacity as well as the passenger flow characteristics of urban rail transit network expanding to suburb were discussed firstly. Secondly, income assignment algorithm and its implementation plan process under the network operating environment were put forward according to the methods and technologies of network operation. Thirdly, the carrying capacity loss calculation method of two lines with joint operation combined with multi-routing operation was studied, and the approach to achieve the maximum carrying capacity and its conditions were brought forward. Finally, a model of express train stop station selection to minimize total travel time and corresponding algorithm were also studied.The main studies and conclusions are as follow.(1) Defined network accessibility matrix by transfer nodes between each two lines. The different accessibilities of parallel, radiation and ring lines in network, as well as two-line transfer and three-wire transfer in transfer station were explored. The results show the different marginal contributions of varying lines to accessibility in rail transit network. Take Tokyo Metro and Beijing urban rail transit networks for example. These two networks have similar sizes, while by comparison, the result shows that the accessibility of the latter is only 40% that of the former. The reason for this difference was analyzed, and relevant recommendations were put forward.(2) The Passenger Flow Distribution (PFD) characteristic of network is comprehensive manifestation of PED of lines in different directions. The study on PED of long lines expanding to suburb shows that the PED of whole line is unbalanced, commuter flow has special impact on the peak flow in the morning and evening, and passenger exchange volumes are obviously uneven among different sections, especially between the urban and suburban sections.(3) According to the essential difference of income assignment under the transfer environment and joint operation environment, an improved income assignment algorithm was proposed. In the course of algorithm construction, a "virtual path" concept was brought forward, corresponding to different operation accounting entities of the same OD. Thus passenger flow distribution could be determined by multi-path selection probability model or stochastic user equilibrium model to achieve income assignment under joint operation environment. Case study shows the validity of the improved algorithm.(4) The carrying capacity of multi-routing line was studied, and the calculation formulas of carrying capacity loss both in single routing interval and double routing interval were put forward. After that, a method to achieve the maximum carrying capacity by extension of back-turning time of long routing was brought forward and its sufficient conditions were deduced. Case study result shows that by extending back-turning time to 110s, carrying capacity loss of single routing interval and double routing interval is reduced by 0.4 trains per hour and 1.2 trains per hour respectively, which verify the validity of the method.(5) Suburban rail transit joint operated with urban rail transit of multi-routing was studied and the calculation formula of carrying capacity loss in each interval was put forward. Then, a method to achieve the maximum carrying capacity by over-rail routing of suburban rail transit line was brought forward, and its sufficient conditions were deduced. Thus carrying capacity loss of urban rail transit line was decreased to zero while that of suburban rail transit line was increased, however, the increased value was lower than the decreased one. Case study result shows that the carrying capacity loss of single routing interval of urban rail transit line is reduced by 13.3 trains per hour by increasing 0.3 trains per hour of carrying capacity loss of suburban rail transit line, which verify the validity of the method.(6) Travel time of the travelers all over a rail line was studied and a model of express train station selection to minimize total travel time was built. This model about multi-objective programming problem was transformed into a single-objective one to design algorithm. This model can also be used to determine whether express/slow train operation is applicable for an urban rail transit line. Case study verifies the validity of the model and algorithm.