Optimal Utilization Of Urban Rail Transit Train On Network

Urban rail transit has become an important component of public transport in major and medium-sized cities in China with its characteristics of mass transportation,safety,energy conservation and environmental protection,and will achieve even greater development in the foreseeable future.In the initial period of development of urban rail transit,the rail network is small in scale and there are few operational lines.The single-line operation mode can meet the requirements.Today,the scale of urban rail transit network is gradually expanding,and network-oriented operation for networks has become inevitable.In this situation,designing a more efficient urban rail train undercarriage for network design will not only help provide better transport services,but also help the urban rail operators reduce operating costs,this makes it a valuable research direction.Based on this background,determine the main research content of this article based on the analysis of existing: to formulate and optimize the use plan of trains for urban rail trains on the rail network,the fleet size,the flow balance,the safety usage interval and other more constraints must be fully considered in the process of formulating the operational plans.The content of the paper is as follows:Design a physical network composed of parking lots,stations and tract lines between stations,and define the relevant symbols of vehicle floor operation optimization in the network;then,taking the minimum cost of traveling as the objective function,the mathematical model for the optimized use of the vehicle base is constructed with the parking lot capacity,train number-vehicle-bottom correspondence,flow balance,and safety interval constraints,and full consideration is given to the vehicle running time and other additional constraints.After completing the mathematical model,analyze it and lead to the space-time network.Designing the time-space discrete network: a complete space-time network is defined and the related symbols are defined according to the layout characteristics of urban rail transit.Reformulate the mathematical model based on physical network in space-time network to facilitate solution,in the reformulation process,linearize the nonlinear constraint by methods such as the theory of large M.After completing the reformulation of the mathematical model,analyze it for the solution process.Designing Different Examples to Solve Linear Models in Space-time Networks: Given the operating data,it is taken into the time-space network to be discretized and then solved by optimization solvers.The example solution results prove the correctness of the mathematical model and the necessity of the optimization of the vehicle bottom application.In the end,the article analyzes and discusses the directions that can further deepen the research in the future,that is,the design of algorithms that can be selected when facing large-scale data such as Lagrangian relaxation.