The Measurement Of Transport Capacity Of Urban Rail Transit Network Under The Condition Of OverSaturation Passenger Flow

Nowadays the public transport is flourishing. The urban rail transit has become the first choice of citizens due to its exclusive advantage. While the railway line is being built, the network of the urban rail transit development, meanwhile some of the big cities have been established already, traffic passengers of urban rail network keep rising and even over saturation. The research basics of early study on the transport capacity are the railway line and station. The computing method for transport capacity of urban rail transit network has not been formed yet while the research of that is in the exploratory stage.Firstly, the paper summarizes the achievement of domestic and foreign research on this topic and gives the definition of the over saturation passenger and the traffic capacity of urban railway. The article also analyzed the influence factors of traffic capacity of urban rail transit network in terms of the character of railway network and passenger flow, level of service and safety of operation.Secondary, the article construct a digraph and use the backtracking and traversal method to get the effective path over the urban rail transit network. It also construct a function of generalized trip cost in terms of operation time, dwell time,walking time of transfer and degree of congestion. What’s more, combined with the OD volume of urban rail transit networkunder the condition of over saturation passenger, transfer passenger flow and section passenger flow are calculated based on an improved Logit model for passenger flow distribution. On this basis, considing transfer passenger flow, rail transit lines transport capacity and distance, the paper put forward the measure method of transport capacity of urban rail transit networkunder the normal circumstance from two calculation index of passenger transport and passenger turnover.Then, the article analyzed the distribution character of passenger flow under the circumstance of accidence and discuss the treatment and principle of passenger flow influenced by accident. Meantime a second passenger flow distribution method under the circumstance of accident is put forward. According to the research abov,author also put forward a method to measuer the railway network transport capacity under the abnormal circumstance involvingpassenger transport and passenger turnover.In the end of the article,by using the fundamental data under the condition of over saturation passenger flow and measure method put forward in the article, the author practically verified the actual traffic capacity of Beijing railway network under the normal and abnormal circumstance.