Optimization Study On Maintenance And Operation Schedule Of Urban Railway Trains

Urban rail transit system is getting the favor of many well-developed cities and expands rapidly due to its efficiency and large capacity.Rolling stock is an important part of the system.The ownership of rolling stock keeps rising due to longer operating length and shorter departure interval.It's a key issue in urban rail operation that is to make a scientific and efficient schedule of vehicle routing and maintenance to reduce operation costs while ensuring safety.This paper conducts an optimization study on the maintenance and routation schedule of urban rail rolling stock.This paper also presents a vehicle maintenance schedule optimization model and a train routing schedule optimization model considering maintenance schedule.In addition,this paper employs a case study to verify the validity of models and algorithms based on urban rail historical maintenance data and timetable.This research paper includes the following three parts:First,this paper analyzes the degradation process of rolling stock subsystem and characteristics of maintenance work in urban rail.The two-stage delay time model is used to describe the subsystem degradation process,and an estimation method of relevant parameters is proposed based on the historical data.Considering the current maintenance strategy and imperfect maintenance theory,with minimum cost as goal,maintenance interval and reliability threshold as decision variables,a multi-level maintenance optimization model for urban rail rolling stocks is established.At last,an optimal maintenance schedule for subsystem is solved,and a sensitivity analysis on several key parameters in this model is also carried out.Secondly,considering the economic correlation among the subsystems,a grouping optimization model for preventive maintenance schedule of a whole train is established.Taking into account that the optimal maintenance time of subsystem will change due to grouping process,a penalty fee that varies with deviation time is proposed as an additional cost in the grouping model.Subsequently,this paper presents an improved algorithm to solve the model.At last,this paper employs a case study based on optimal maintenance schedule of subsystems.Finally,based on the timetable and maintenance schedule,considering the relationship between operation schedule and maintenance schedule,an optimization research on rotation schedule is carried out.This paper presents a single-day turnover schedule optimization model and a rotation optimization model with considering maintenance schedule,which optimize single-day operation tasks and multi-day rotation schedule sequentially.An improved ant colony algorithm is proposed to solve this model.At last,this paper employs a case study of real urban rail line.The result shows that the optimization model and algorithm can effectively generate a feasible train routation schedule.Compared with the current plan,the number of used trains and the train utilization deviation is optimized.In addition,compared to the current maintenance schedule,the optimized maintenance schedule in this paper can further reduce the number of used trains and the operating cost.