Optimization On Service Plan Considering The Decline Of Vehicle Dispatching Capacity From Metro Depot

In order to ensure the supply of transportation capacity during the morning peak hours,the depots are arranged to be densely launched at the bottom of the vehicle in advance,and their departure capacity is closely related to the operational efficiency of the main line.If the departure capacity of the depot is reduced,it will cause the delay of the vehicle to go online,which will lead to a mismatch between the capacity and passenger flow demand during the morning peak hours,which will seriously affect the passenger service level.To this end,it is necessary to optimize the train schedule from the start of the subway operation to the morning rush hour when the depot capacity decreases.In this paper,by analyzing the depot departure operation process,the train crossing plan and the turnaround operation process,taking the double-depot subway line as the research object,and based on the existing mode of operation of the large and small intersections,an optimization model for the preparation of the train plan under the condition of reduced departure capacity is constructed,and then design a genetic algorithm to solve it.Finally,the feasibility and applicability of the model are verified by taking Shanghai Metro Line 1 as an actual case.The main work and conclusions of this paper are as follows:(1)Analyze the problems related to the preparation and optimization of the driving plan.Firstly,the starting operation process of the depot is analyzed,and the influencing factors are summarized,including the signal system,the power supply system,the design of the entry and exit lines,and the layout of the signals and switches in the throat area.Secondly,it analyzes the applicability of the large and small traffic mode.The mode can reasonably distribute the transportation capacity according to the spatial distribution characteristics of passenger flow,and is widely used in the diameter lines and suburban lines of major cities in my country.Finally,by analyzing the process of train turn-back operation,the turn-back capability constraints under different turn-back modes are obtained.(2)An optimization model for the preparation of the train plan under the condition of the decrease of the starting capacity is constructed.The model takes whether the train starts,the departure time of the train,whether the trains are connected and whether the vehicle bottom is a newly launched vehicle bottom as the variables.and other constraints,the train departure interval,the route plan and the bottom turnover of the train are optimized with the goal of minimizing the total number of passengers stranded.(3)The variables and constraints of the model are analyzed,and a solution strategy combining genetic algorithm and linear solver is proposed.The genetic algorithm is used to solve the number of trains and departure times and the number of passengers staying in the objective function.In the process of population initialization and each iteration,the linear solver is called to modify and supplement the individual,so that the individual becomes feasible and the remaining number is calculated.Vehicle bottom-related decision variables.(4)The model is applied to Shanghai Metro Line 1,and the feasibility and applicability of the model are verified through actual cases.Based on the actual operation data,the driving plan under the condition of limited departure capacity of the depot is optimized.The results show that the maximum number of stranded people per train is less than the platform capacity,which verifies the feasibility of the model.Through the experimental analysis of the influence of the location of the turn-back station on the small intersection on the results,it is found that when the small intersection covers both the upward and downward passenger flow sections,the number of stranded people is reduced by 33.6%.The results after changing the turn-back capability of the railroad station in the faulty depot show that when the turn-back capability is reduced,some large traffic trains turn back in advance to relieve the turn-back pressure at the terminal station,and the logarithm of small traffic trains increases.In both scenarios,the maximum number of stranded people per train is smaller than the platform capacity,which indicates that the model can flexibly open large and small crossings according to the coverage of small crossings and the turn-back capability of line end stations,distribute capacity reasonably,and reduce passenger retention.