Analysis Of Departure Mode About Freight Train In Marshalling Station And Research On Optimal Strategy

The great achievement of China in economic development provided the powerful motive force for the development of railway transportation. With the economic progress of China, the contradiction between railway supply and transportation demand has been relieved greatly. The modes used by China are as the following:enlarging the railway network scale, building Passenger Dedicated Line, updating the technical equipment, developing the heavy load transportation, enhancing the velocity of trains etc. Furthermore, for the adaptation to the demand to railway transportation of shipper in the new period, the Railway Department has adopted some effective measures, such as pushing out "Five Schadued" trains, Railway Luggage and Parcel Express Special Train etc. new goods transportation variety, compressing the number of marshalling station, increasing the running proportion of through trains, and accelerating the development of container transportaion and so on, which improved the service quality in goods transportation.But, the proportion of the goods trains which are reorganized in marshalling station is still the main portion of railway goods transportation in my country. Presently, besides that the railway supply can't meet the transportation demand, it is an outstanding problem that the timeliness of railway goods transportation is not good. Now, the making-up type train-running organization system is still adopted in our country. To enhance the quality of transportation completely, and improve the timeliness of railway goods transportation, only depending on increasing the ability of the railway transportation is not sufficient. We must also reform the train-running organization system of our country. However, the optimization of organization in marshalling station is the key question in the reformation of railway train-running organization.The research on optimization of departure mode in marshalling station is very important for our country to guide the reformation of train-running organization and enhance the service quality. The thesis takes the theoretical research as the core, references the outcome of the past research and adopts the systematic view, appllies the correlative theories such as transportation organization, optimization theory, mathematical statistics and systematic science etc. to study the relevant parameters and the laws deeply. The contents of the thesis include the following several aspects mainly:(1) The optimization of departure mode is analyzed systematically. According to the three kinds of constraint when the train is marshaled in marshalling station, the departure modes are divided into three kinds of modes. Furthermore, the question to optimize the departure modes is transformed into how to find the optimal minimum number of cars.(2)The statistical law about car flow's arrival is analyzed by the method of mathematic statistics. And furthermore, it is pointed out that the statistic analysis of data must be made by time segment, which makes the law about car flow arrival accord better with the actual situation. When the arriving law of car flow changes, on the condition that the sample size is not sufficient, a kind of Bayes estimation method for the arriving law of car flow is given.(3) In order to measure accurately the change of transportation cost caused by the different departure modes, the comprehensive influence to the operation organization of marshalling station which is caused by the difference of departure mode is analyzed synthetically. It is pointed out how the change of the minimum number of cars to influence the marshalling-departure system and the arrival-disintegration system. What is more, the influence to the departure order and the departure proportionality which is caused by the change of the minimum number of cars is studied by the simulation method.(4) The process that the cars are assembled, marshaled and sent out is considered as a system. According to the comprehensive analysis to the synthetic influence caused by the difference of departure modes, the method to measure the change of transportation cost which is caused by the difference of departure modes is given. In this calculation process, a proper method to compute the transportation cost is adopted according to the arrival law of car flow and related constraint in the process that the cars are assembled, marshaled and sent out.(5) On the basis of analysis and reference to the past departure strategy about good trains in the marshalling station, a optimization model about the departure mode is established. And at the same time, a compute formula about the minimum number of cars is given by the optimal criterion of expectation. Moreover, the property of the minimum number of cars is analyzed by this formula. Because it is difficult to determine the parameters in this formula, the thesis gives a method to determine the optimal minimum number of cars by simulation. Besides, some concepts related to determining the optimal minimum number of cars is put forward.(6) After having analyzed the condition in which the owing-axis departure is favorable, the thesis studies the question that how the owing-axis goods train is attached operation. Furthermore, the thesis gives two kinds of method to use the ability of the owing-axis goods train. The two ways are adding cars which violate the marshalling plan to the owing-axis goods train and attaching operation in the midway station, respectively.(7) The steps to determine the optimal minimum number of cars is given by an example. And the idea that the statistic analysis of data must be made by time segment is verifed.The study covers the principal relevant contents as to the optimization of departure mode, in the hope of offer a certain theoretical support and reference for the reformation of train-running organization system, and playing a certain promotion role to the reformation of the railway running-train organization system.