Research On Buffer Time Setting Of High Speed Railway Train Diagram

The high-speed railway of China is currently in the stage of rapid development.By the end of 2019,the operating mileage of China’s high-speed railway has reached 35,000 kilometers,ranking the first in the world.The proposal of "eight vertical and eight horizontal" high-speed railway network represents the grand blueprint of China’s high-speed railway network construction.The rapid development of high-speed railway cannot be separated from its high-quality transportation service.The safety,high speed,punctuality and comfort of high-speed railway make high-speed railway occupy an indispensable position in the transportation market.The operation of high-speed railway cannot be separated from the train operation diagram.The quality of the train operation diagram directly determines the quality of the actual transportation organization service.However,there are always factors that disturb the order of operation.According to Murphy’s Law,which holds that things always go bad,it is natural for the high-speed railway train operation to meet something that will negatively influence its normal operation;and the direct result of it is the deviation from the original train operation diagram.Therefore,the train operation diagram should have some elasticity to improve the ability to cope with interference.Adding buffer time to the train operation diagram is an efficient way to improve its elasticity.This paper takes the high-speed railway train operation diagram as the research object and studies the setting of buffer time.Based on the examination of a large number of domestic and foreign related research,this thesis offers a clear definition of the buffer time in high-speed railway train running,analyzes its characteristics of uneven distribution,small number,and flexible existence,and explores its contribution to improving the safety,punctuality,and elasticity of train running.The thesis also further analyzes the generation mode of buffer time from the two aspects of natural generation and artificial setting.With the help of these findings,the thesis then looks into the factors that influence buffer time,and reveals that the setting of buffer time is mainly affected by the layout structure of operating diagram,interval passing capacity and train delay rate.Based on the analysis of the characteristics of the train operation diagram of high-speed railway,the structure of the train operation diagram is described from the aspects of train operation line,station line,train interval running time,train stop time,tracking train interval time and skylight time.On this basis,the distribution category of buffer time in the operation diagram is analyzed.Affected by the structure of the train operation diagram,buffer time can mainly exist in the running time of the interval,stop time,tracking train interval time and standby running line.For a train line,the buffer time is mainly distributed as follows: evenly distributed in the operation diagram gradually increasing with the train operation,concentrated in the last section or station distribution.This thesis analyzes the characteristics of the delay of high-speed railway trains in China,classifies the delay according to different standards,and points out the factors that cause delay.By analyzing the regularity of train delay,it can be known that the distribution of delay frequency follows Poisson distribution,and the distribution of delay interval follows exponential distribution.By establishing the relation between train delay and queuing model.And providing the assumed conditions for model establishment the delayed train of high-speed railway can be transformed into a queuing model.And in this way,the thesis reveals the relation between buffer time and train delay,and uncovers the limited conditions to get buffer time.Finally,taking Wuhan-Guangzhou high-speed railway as an example,the buffer time setting of Changsha South Railway Station,Hengyang East Railway Station and Guangzhou South Railway Station on Wuhan-Guangzhou high-speed railway line is calculated based on certain delay conditions,and the reference value of buffer time setting is given.