Research On The Compilation Method Of Special Train Operation Graph Of Urban Rail Transit Under The Epidemic Situation

In recent years,the new coronavirus epidemic has been repeated,and the urban rail transit operation with dense passenger flow is facing arduous challenges.In order to prevent the wanton spread of the new coronavirus,the Ministry of Transport pointed out that it is necessary to control the full load rate of trains.Compared with the traditional single intersection,the flexible operation of trains on small intersections can reduce the turnaround time and improve the capacity of large passenger flow sections under the condition of limited vehicle resources.On the other hand,opening large and small traffic routes can realize the precise delivery of transportation resources,improve the matching degree between transportation volume and transportation capacity,reduce the waste of transportation resources as much as possible,and realize cost reduction and efficiency improvement.Therefore,opening large and small intersections is the key to reducing the full load rate of urban rail transit trains during the epidemic,while saving the cost of operating companies.In this paper,an automatic compilation model of special train operation diagrams facing large and small intersections under the epidemic situation is constructed.The specific research contents are as follows:(1)With the goal of reducing the full load rate of trains,using the cross-section spatiotemporal passenger flow data as input parameters,an optimization model based on Mixed Integer Linear Programming(MILP)was constructed to optimize the urban rail transit plan for large and small intersections.And use CPLEX to solve the model to obtain the train operation plan,the number of vehicles used for large and small intersections,and the optimized train full load rate.Finally,the Beijing Subway YIZHUANG Line is used for example verification and simulation.The simulation results of the example show that the best effect is to set Tongji Nanlu as the turning point of the small intersection.During the peak period,there are 8 trains running on the major intersection and 14 trains running on the small intersection.After optimization,the maximum full load ratio of up and down is optimized.The previous full load ratio of the upstream and downstream has been reduced by 17.5% and 37.9% respectively;during the peak period,3 trains will run on the large traffic road,and 15 trains will run on the small traffic road.rate decreased by 8.4% and 8.6%,respectively.(2)An optimization model for the preparation of train operation diagrams in high and flat peak hours for large and small intersections is constructed.Under the condition of known operation plans,various factors of train operation diagrams are considered,such as train operation time constraints,stop time constraints,Constraints such as vehicle bottom turnover constraints,departure interval constraints,and turn-back time constraints are used to establish an automatic compilation model of train operation diagrams,and CPLEX tools are used to solve the model.The simulation results of the example show that the optimization can achieve a maximum full load rate of 40.5% for the upward trains and 42.8% for the downward trains during peak periods.During the flat peak period,the optimization can achieve a full load rate of 49.2% for the upward trains and 49.2% for the downward trains.The full load rate is 38.1%.(3)An operational research optimization model for the preparation of train diagrams in the transition period for large and small intersections is established.Firstly,a three-stage model is proposed.In the first and second stages,the intersection model is assumed to be a conventional intersection,and the sequence numbers of the return/outgoing trains are determined,and the train operation diagram between this period and the high and off-peak hours is realized.transition.The third stage decides whether the trains in the regular traffic turn back halfway,so that the intervals between the trains are even.Then the model is solved by CPLEX,and the simulation results of the example show that the model can calculate the number of trains and the number of trains on the return,and ensure that the train operation graph is evenly drawn as much as possible,and can meet the requirements of the train operation graph during the transition period from peak to flat peak.