Research On Feeder Bus Service For The Emergency Of Rail Transit

With the development of the city,urban rail transit has been playing an increasingly important role in the urban public transportation system.However,due to some inevitable reasons in daily operations,the emergencies of urban rail transit occur frequently.Once rail transit is interrupted by the emergencies,it is easy to delay a large number of passengers.If it is handled improperly,it may cause further deterioration of the situation and even affect the transportation system of the whole city.Therefore,after an emergency occurs on rail transit,the operators should respond to the emergency in time.As one of the important response measures for rail transit emergencies,feeder bus can evacuate passengers timely and ensure successive transportation within the affected area.The interruption of rail traffic operation due to the emergency is selected as the research background.The feeder bus service in the interrupted rail transit network is taken as the research object.This study utilizes the theory of graph theory and optimization to conduct an in-depth study of the impact of feeder bus services on the robustness of interrupted network and the optimized scheme for setting the feeder bus lines.The research contents of this study are as follows:(1)Based on the summary of the research results of rail transit emergencies,this study elaborates on the connotation,definition and classification of rail transit emergencies.The emergency management system and emergency management strategy under rail transit emergencies are summarized,and they are treated as the organizational foundation and institutional foundation to feeder bus service respectively,laying the foundation for subsequent analysis.(2)Based on graph theory,the topological structure of the rail transit network before and after the emergencies was established.And this study establishes a robustness evaluation model for rail transit networks that consider feeder bus services.Passenger flow is classified according to the affected form and subsequent travel behavior of passengers.According to different types of passenger flow,three research cases are selected.Corresponding to each case,the initial OD matrix is adjusted and discounted.The passenger flow of OD matrix is assigned to the sections in network by MATLAB software,and then the robustness change of network between various cases is calculated and compared.In addition,all sections in network are divided into line sections and transfer sections to evaluate the robustness of the network with or without the transfer situation.Based on the AFC card data,the results of the robustness change of the rail transit network considering the feeder bus service are solved by using MATLAB.This case study indicates the effectiveness of feeder bus service to improve the robustness of rail transit networks.(3)The setting method of feeder bus lines in the rail transit interrupted area is ed as a nonlinear optimization problem.A feeder bus optimized scheme that comprehensively considers traditional feeder bus lines and nonstop feeder bus lines has been formulated.This study proposes an equivalent accumulative method of passenger flow in the interrupted area under emergencies.In the optimization model,the comprehensive objective function is determined from two perspectives:the travel time of passenger and operating cost of feeder bus.The load factor of lines,the number of buses,the waiting time of passengers,the number of bus lines,and the departure interval are the restricted conditions.(4)A case study was conducted for the situation in which an interruption of emergency occurred on the subway network consisting of four lines of the Beijing Subway.Based on the generalized reduced gradient method,LINGO is used to seek for the optimized scheme of feeder bus lines in the interrupted area.This case study examined the reliability of the optimized model and the economics of the optimized scheme.It provides a reference for traffic operators to respond to the rail transit emergency by using feeder bus services.