Research On Optimization Model Of Empty Car Dynamic Distribution Based On Time-space Network

The empty car distribution, being the main part of the railway transportation plan, is an important means to realize effective distribution of the railcars resource, to insure railway proportion transportation, to increase the rate of railcars and to make transportation production in order. At present, there are about 568,500 freight cars, and the average ratio of empty car kilometers to loaded-car kilometers is about 40%, the maximum ratio is greater than 50%. To those railway enterprises, it now becomes a big problem which attracts more and more attention to find out how to increase the efficiency of the empty cars and the competition ability of railway in transportation market, which is aim of railway market-oriented reform. Affected by too much subjective and objective factors, empty car distribution problem has not been solved thoroughly on both theory and practice, which remains an important theoretical and practical research task.In recent 30 years, empty car dynamic distribution has been a popular topic in many developed countries. However, it hasn't received more attention in our country because of the characteristics of large-scale railway network, limited transport capacity, and planned economy. In practice, the scheme of dispatching empty cars changes from time to time follows the fluctuation of freight demand and train connection. So, the scheme, laid out by static planning method and historical experience, is unscientific and unhelpful for proper allocation and maximum utilization of empty car resources.Based on researches on the problem at home and abroad, this dissertation constructs a optimization model of empty car dynamic distribution which is close to our railway operating features, and proves that the model has a better practicability in railway enterprise through a practical example.There are three main innovative aspects in this paper, which are presented as follows:1. Based on the time-space network and from the point of speeding up railcars circle, it greatly reduces the time of empty cars stay at the station;2. It clears up the route of every empty car flows in railway enterprise and their final destination;3. Consummate the model and make the result more accord with the train diagram.