Study On The Comprehensive Optimization Of Train Formation Plan And Flow Path Based On Uncertain Parameters

The wagon flow organization is the foundation of transportation organization and management work. The train formation plan is the concrete embodiment of the wagon flow organization. In the past twenty years, the optimization problem of the train formation plan was being a hot issue. The comprehensive optimization of the train formation plan and flow path even has become the key research object for experts and scholars in recent years.In the traditional optimization methods of the train formation plan, main parameters wagon flow, wagon assembly time and wagon shunting additional time have been always assumed constant. However, these three parameters are fluctuating with time changing which can not make the "optimal" marshalling scheme obtained from the traditional optimization model of the train formation plan achieve the so-called "optimal" effect in the practical application. The optimization problem of the train formation plan taking into account the volatility of parameters to find the optimal marshalling scheme and flow path, is of great significance not only in the actual transportation and production but also in theory. And this has become a problem which needs to be solved urgently in the field of wagon flow organization.The volatility of wagon flow, wagon assembly time and wagon shunting additional time were taken into account in the optimization problem of the train formation plan in the thesis. And the theory of chance-constrained programming and fuzzy chance-constrained programming in the stochastic simulation and fuzzy simulation methods were used for the volatility of the parameters'mathematical treatment. And the comprehensive optimization model of single-group technical through train formation plan and flow path based on uncertain parameters was built. Then characteristics and degradation of the model was analyzed. After degradation, the model was a programming model 0-1 whose objective function and constraints were all weakly nonlinear. For the model features the improved branch and bound method based on stochastic simulation was designed, and LINGO mathematical tool was used to solve the model, and the basic steps of optimization algorithm were put forward. Finally the model and algorithm were examined by a small railway network. The fact that optimal solution of the comprehensive optimization model of train formation plan and flow path based on uncertain parameters was of greater stability than the model based on certain parameters was found by solving the models based on doing and not doing take into account the fluctuation of the wagon flow. Besides, computing speed of optimization was also satisfactory.After systematic study on train formation plan and flow path comprehensive optimization problem in the case of parameters fluctuating, we get some useful conclusions and provide some new ideas for the wagon flow organization optimization. But in the same time, because of author's limited knowledge and time, there are still many problems to be improved and studied in-depth in the formation plan optimization problem in the case of parameters fluctuating.