Research On Capacity Of Urban Rail Transit Based On Blocking Time

Urban rail transit is the best solution of public transportation problems in large cities, and the transport capacity is the manifestation of meeting the public needs for urban rail transit system. As an important component of urban rail transit system, the signal system plays a fundamental decisive role on determining the transport capacity. From the perspective of the signal system, how to assess the transport capacity and find measures to improve it will be of great help to make operational decisions for managers.From the definition of transport capacity, this paper proposes an index system for assessing the transport capacity, which is consisted of the minimum headway, the operation speed and the equipment utilization rate. In this index system, the minimum headway, the operation speed and the equipment utilization rate respectively reflect the line volume, the operation quality and the line congestion tendency.By analyzing the lack of the train tracing model, the paper establishes the blocking time model of the line, the station and the tumback at the terminal for the fixed block signal system and the moving block signal system respectively. Based on the analysis of the blocking time models and the factors impacting on transport capacity, the paper designs and establishes a simulation method for assessing the transport capacity.By the simulation method, the paper obtains the assessment indexes of the fixed block signal system and the moving block signal system. After analyzing the assessment indexes the paper finds that although the operation speed's variation is not obvious compared to the fixed block signal system, but the moving block signal system makes the line volume increase and the line congestion tendency down. Through the simulation method, the paper quantitatively analyzes the factors of the signal system which impact on the transport capacity and come to the most feasible way to improve the transport capacity. In order to improve the transport capacity, the distance between the balise and the signal should be shorten within the reasonable limits for the fixed block signal system, and the train speed should be adjusted to the optimum range for the moving block signal system, and then the line volume will achieve maximum.