Research On Collaborative Optimization Of The Construction Skylight And Train Operation Diagram Of Busy Railway Main Lines

In response to the problem of tight transportation capacity on the busy trunk lines of passenger and freight railway,railway departments need to continuously reduce the impact of construction skylight on the passage capacity of the trains during the coordination of construction and maintenance operations and train conflicts to ensure the safe operation of trains.Because the actual train operation diagram involving construction skylights is prepared step by step with subjective factors,lack of systematic theory and method support,it is difficult to effectively avoid the impact of construction skylight on train operation lines.Therefore,this article conforms to the reform direction of railway freight transportation,from the perspective of matching transportation capacity and transportation demand,with the goal of optimizing the passage capacity of the section,collaboratively optimizing the construction sunroof and train operation line,and optimizing the train operation diagram in an overall manner.The work content is as follows:(1)Summarize the shortcomings in the domestic comprehensive research involving construction and maintenance operations,section passing capacity and train operation chart compilation,clarify the shortcomings of the train operation chart step-by-step compilation and the necessity of collaborative optimization of the construction skylight and train operation line.On this basis,the operation content and different opening methods of the construction skylight are introduced,which provides a basis for the selection of a single "V-shaped" construction skylight in this article.Finally,the calculation method of section passing capacity and the influencing factors of the quality of train operation diagram compilation are summarized,and methods to improve the section passing ability and train operation diagram compilation quality in this paper are selected to provide theoretical support for the establishment of the following model.(2)Establish a collaborative optimization model of construction skylight and train operation diagram.Combining the existing research,the modeling idea of collaborative optimization of construction skylight and train operation line is proposed,including the feedback mechanism of construction skylight and train operation line and the opening plan of construction skylight,and the focus is on the freight train operation line.The goal is to maximize the total mileage of freight trains and minimize the total stop time of affected trains.A double-objective mixed integer programming model for collaborative optimization of construction skylight and train diagram is established.(3)Designed and improved the algorithm for solving the collaborative optimization model of construction skylight and train operation diagram.First,the solution of the model is proposed,and the basic principles of the selected NSGA-Ⅱ algorithm are introduced.Secondly,combined with the characteristics of the cooperative optimization model of construction skylight and train operation diagram,the NSGA-Ⅱ algorithm is designed and improved to improve the three aspects of non-dominated sorting,congestion calculation and selection strategies to enhance the global search effect of the algorithm.Finally,the processing method of the solution result and the cooperative optimization processing flow of the construction skylight and train running line in the algorithm are proposed.(4)Calculation example verification.First,using small-scale calculation examples,CPLEX and improved NSGA-Ⅱ algorithm are used to solve the problem,and the comparison is used to verify the correctness of the model and algorithm.Secondly,based on the Tianjin-Dezhou section of the Beijing-Shanghai general speed railway,a large-scale example was designed and solved using the improved NSGA-Ⅱ algorithm.By comparing with the actual train operation diagram,an optimized train operation diagram suitable for this section was obtained.Finally,based on a large-scale example,the results of the improved NSGA-Ⅱ algorithm are compared with those of the classic NSGA-Ⅱ algorithm,the results of the step-by-step compilation method and the results of the traditional genetic algorithm to verify the effectiveness and optimization of the models and algorithms in this paper.