Construction Of Impedance Function And Prediction Of Wagon Dwell Time In Marshalling Station Based On Simulation

As an important node of the railway network,the marshalling station undertakes the transportation and production task of the freight trains.The dwell time of the freight cars passing through the marshalling station accounts for a large proportion of the total turnover time,which is the key part of the freight car turnover speed.This paper studies the relationship between the wagon flow of marshalling station and the stay time of freight cars in the station from the macro level,in order to predict the average stay time of freight cars in the marshalling station through the wagon flow,and provide the basis for analyzing the timeliness of goods delivery,the operation efficiency of marshalling station,or studying the node capacity and node assignment of railway network.The dwell time of freight cars in marshalling station reflects the resistance level of the station.In this paper,the concept of marshalling station impedance is introduced,that is,the average dwell time of freight cars in the station is used to represent the difficulty of wagon flow passing through the marshalling station.The average dwell time of freight cars corresponding to different wagon flows is obtained through simulation.The impedance function of the marshalling station is constructed by regression analysis based on BPR and other road resistance functions.The impedance function is used to express the relationship between the arrival wagon volume and the dwell time of freight cars.Based on the impedance function of marshalling station,the average dwell time of freight cars can be predicted according to the arriving wagon flow,and the impedance level of marshalling station under different wagon flow is determined.The main work of this paper is as follows(1)From the perspective of technical operation process of marshalling station,this paper analyzes the influencing factors of wagon dwell time,which provides the basis for parameter setting of marshalling station simulation model.In addition,the statistical law of the arrival of train flow in the marshalling station is analyzed to determine the input of train flow in the simulation experiment.(2)Based on the Anylogic simulation software,the simulation model of marshalling station is constructed from three aspects: entity layer-marshalling station simulation scene,logic layer-simulation logic flow and data layer-data statistics and visualization,and the marshalling station simulation experiment system for generating relevant statistical data is developed.(3)The simulation experiment system of marshalling station is used to obtain the different wagon flow data and the corresponding average dwell time data of freight cars at the arrival yard,the shunting yard,the departure yard and the whole station under the two hump operation modes of single push single slide and double push single slide.Based on the least square data fitting method,the nonlinear regression analysis of experimental data is carried out on the basis of BPR function and other road impedance functions,and the impedance functions of marshalling stations and depots under two hump operation modes are determined by comparing the fitting results.(4)Taking Fengtaixi Marshalling Station as an example,the simulation model of Fengtaixi Marshalling Station is constructed.Through the simulation,the maximum wagon flow and the minimum average dwell time of freight cars are determined,and the impedance function of Fengtaixi Marshalling Station and each depot is obtained.Based on the actual wagon flow data of Fengtaixi Station,the effectiveness of impedance function is verified.Based on the impedance function,the average dwell time of freight cars in Fengtaixi Station under the condition of large wagon flow is predicted.