Research On Centralization And Optimization Of The Layout Of Car Inspection And Maintenance

The layout of railway freight cars inspection and maintenance center is very important in railway, is related with the layout of railway freight stations. The rational layout can decrease both the cost of all cars inspection and maintenance, and the period of time that cars were overloaded and the probability cars missed to detect. Then the operation safety of railway will be ensured, cars velocity will be quickened and the investment of railway cars will be reduced. The spanning development report of Ministry of railway put forward that the layout of the productivity of railway transportation should be modulate revolutionary, resource of cars inspection and maintenance should be centralized, then economies of scale can be formed.The conception of centralization of freight cars inspection and maintenance is put forward. After economic of centralization of freight cars inspection and maintenance is analyzed based on scale and scope economics theories, economies of scope of cars model and repair are defined and performing centralization of freight cars inspection and maintenance can conclude that benefits of scale and scope economics can be received and diseconomy of network nodes can be abated.The optimized cars inspection and maintenance center layout is studied emphatically. Based on the analysis of interrelated expenditure, a bi-level programming optimization model for the layout of cars inspection and maintenance center is established. The objective of the upper programming is the minimum total of investment, working capital and transportation cost, and the objective of the lower programming is the minimum transportation cost. Because of complex property, a simulated annealing algorithm is applied in solving the upper programming, whose convergence is quickened through solving the lower programming. Considering the practice, the programming of the lower programming problem is transformed into the minimal cost maximal flow. By the method, the bi-level programming optimization model is solved well.With research on the delimitation based on network of center'sradiation, radiate model of centralization of freight cars inspection and maintenance is established, and three kinds of dimensions are put forward.At last, as an example, economic of centralization of freight cars inspection and maintenance of LIUZHOU railway bureau is analyzed, then economy of centralization is rational. The bi-level programming optimization model and the algorithm are practised, the practical calculation shows the model and the algorithm have better applicability and utility is worthy.