The Theoretical Research Between Fixed-time And Fixed Train Length Of The Traffic Flows In Marshalling Yard

Rail transportation plays an important role in our national economy,it also plays a key role in guaranteeing social demands and economy fast development.As China's economic development,people put forward higher requirements to quality and quantity of passenger and freight transport.For the adaptation to the demand of railway transportation from the shippers,the railway departments have adopted some new transportation measures,such as pushing out "Five Scheduled" trains,Railway Luggage and Parcel Express Special Train etc.By compressing the numbers of reorganization and increasing the running proportion of through trains,the service quality of the freight transportation is improved to some extent.However,most railway freight trains are reorganized in marshalling station,which leads to the timeliness of railway freight transportation is bad.To enhance the quality of transportation completely,and approve the timeliness of railway freight transportation,it is significant to reform the train-running organization system except increasing the ability of the railway transportation.Changing the fixed train length accumulation to the fixed time accumulation is so important for railway department to guide the reformation of train-running organization and enhance the service quality.In order to select a better accumulation which is advanced technology,cost minimization and reasonable,the paper will theoretically researches the economic conditions of the two accumulations.To achieve the above-referred goals,the queueing models of the fixed train length accumulation and the fixed time accumulation in accumulation-marshalling system and breaking-up system of the front marshalling station are built based on the theory of random service system(or queuing theory),and the related indicators of the queueing models are obtained.The saving economic benefits of the traffic flows of different directions with the fixed time accumulation are obtained by the expenditure rate method.The economic applicable conditions of the two accumulations are obtained by analyzing the influences of running trains use-coefficient,traffic flows,section distances,and hump loads.The main contents and conclusions of the dissertation are as follows.(1)The marshalling yard is divided into five queuing service systems:receiving system,breaking-up system,marshalling system,starting system,departure system.The research analyzes queueing process and relevant indicators and parameters of the five queueing service system.(2)The accumulation modes are divided into two modes according to the main document,one is fixed train length accumulation mode with the full axis constraint conditions,and the other is fixed time accumulation mode with the fixed departure time constraint conditions.The merits and demerits of the two accumulation modes are obtained at last.(3)The statistical law about traffic flows arrival is analyzed by the method of mathematic statistics,traffic distribution assumption is tested by the Pearson criterion.(4)The queuing models of the fixed train length accumulation and the fixed time accumulation in accumulation-marshalling system are built based on the queueing theory.The saving time and the more departure trains of the fixed time accumulation compared to fixed train length accumulation are obtained by the queueing models.The saving time of the fixed time accumulation decreases with the increase of running trains use-coefficient and traffic flows by analyzing the influence of running trains use-coefficient and traffic flows.(5)The queueing models of the fixed train length accumulation and the fixed time accumulation in breaking-up system of the front marshalling station are built based on the queueing theory.The saving mean detention time and hump locomotives time of the fixed time accumulation compared to the fixed train length accumulation are obtained by the queueing models.The saving mean detention time of the fixed time accumulation increases with the increase of traffic flows by analyzing the influence of traffic flows.(6)The saving economic benefits of the fixed time accumulation compared to fixed train length accumulation are obtained with the expenditure rate method.There are 5 index values changed by using the fixed time accumulation which are freight car-hour,locomotive kilometer,locomotive hour,locomotive crew hour,shunting locomotive hours.The saving technical economic benefits of the fixed time accumulation of the directions 1-4 in Shan haiguan marshalling yard are 271.38?137.33?-2090.85?-3168.83(yuan)by putting relevant parameter values into the technical economic benefits formula,and the saving technical economic benefits per truck are 2.58?0.64?-6.79?-10.29(yuan).(7)By analyzing the influences of the running trains use-coefficient,traffic flows to the technical economic applicable conditions of the two accumulations,the main of the dissertation are as follows:1)The saving technical economic benefits are mainly decided by traffic flows and running trains use-coefficient.In a small scale(the numbers of departure trains of train scheduling are constant values),the saving technical economic benefits of the truck using the fixed time accumulation decreases with the increase of the running trains use-coefficient;However,analyzing the entire tendency,the saving technical economic benefits of the truck using the fixed time accumulation fluctuation decreases with the increase of the traffic flows;2)Near the inflection point of the running trains use-coefficient,the saving technical economic benefits of smaller traffic flows and larger running trains use-coefficient are smaller than the saving technical economic benefits of larger traffic flows and smaller running trains use-coefficient.