Optimization For Train Service Plan With Full-length And Short-turn Routes On A Metro Line

In recent years,China’s urban rail transit has developed rapidly,and the operation mileage and passenger capacity of the urban rail transit have increased year by year with the continuous expansion of the city size.Affected by various factors such as route conditions,passenger flow characteristics,vehicle configuration,and capacity configuration,the operation organization of urban rail transit will be more flexible and diversified.Therefore,now many cities have begun to try to use the multi-routing operation mode,and in which the full-length and short-turn routes operation method is the most widely used.This paper studies the train operation plan of full-length and short-turn routes,and the main content contains:First of all,this paper analyzes the main influencing factors of the establishment of the train operation plan of full-length and short-turn routes,including passenger flow,transportation capacity,and transportation resources,and expounds the establish principles and method steps for the train operation plan.Then,this paper makes a detailed statistical analysis about the basic situation of 55 lines in 14 cities with full-length and short-turn routes in China from the aspects of line characteristics,passenger flow and train operation organization,and analyzes some typical examples,which lays the foundation for constructing the optimization model of full-length and short-turn routes.Secondly,against the background of the diameter-type on metro line,the optimization model of train operation plan of full-length and short-turn routes is established.When the passenger flow data and other related operational parameters of the line are known,the constraints of the model are the largest line carrying capacity,full load rate constraints and the most suitable positions of the turn-around station,etc.,and the objectives of the model are to minimize the total costs of passengers waiting time,train travel distance and train purchase.and then genetic algorithm are applied to solve the model.Finally,selecting the diameter-type line of Nanjing Metro Line 3 as the research object,passenger flow data and other line parameters as known conditions,using above algorithm to solve the model.we can get the optimal turn-back stations of the short-turn sections and the optimal frequency of trains for full-length and short-turn routes in the early peak period.Compared with the single route,the results show that the number of purchased trains has been reduced from 81 to 72,the total costs have been reduced by5.14%,and the full load rate of the whole line is more balanced.Sensitivity of results related factors are also analyzed,such as the maximum full load rate,the departure ratio of trains with full-length and short-turn routes,and the proportion of passenger traffic in short-turn sections.It can be concluded that the full-length and short-turn routes operation mode is conducive to accelerating the turnover of trains,reducing the number of operating trains,balancing passenger flow,and improving the imbalance of full load rate during peak hours.At the same time,operating companies can put capacity more accurately and reduce operating costs.