Safety-Oriented Prevention Of Urban Rail Transit Train Operation Plab And Timetable Optimization Research

Serious public health and safety events endanger the lives and health of the people.The Corona Virus Disease 2019 is one of the global public health and safety events that have had a wide range of impact,caused great harm and had a deep impact in recent years.As an important mode of transportation driving urban development,the urban rail transit,with its large flow of people and confined and narrow service area,especially inside the train cars,is extremely vulnerable to the rapid spread of the epidemic over a large area,affecting the safety and control of the metro.The train operation plan and timetable are an important part of metro operation.An unreasonable operation plan will not reduce the risk of epidemic transmission,but also waste additional operation costs,which is not conducive to the sustainable operation of metro operating companies.Few studies have been conducted on the operating plans and timetable in the context of the epidemic.In this paper,we propose a risk assessment index for different sections of urban rail lines with significant passenger flow and optimize the train timetable and the number of trains and train crossings in the operation plan,to reduce the risk of epidemic transmission while minimizing the cost of metro operation.The aim is to reduce the risk of epidemic transmission while minimizing the cost of subway operation,to provide guidance to metro operators,and to provide decision-making ideas for possible events of the same situation.The main research of this paper is as follows:(1)This paper introduces the concept of time-varying passenger flow as the basic data and clarifies that the formulation of metro operation plan needs to be based on the characteristics of spatial and temporal distribution of passenger flow,and introduces the evaluation formulas of time and space dimensions for judging passenger flow.The concepts of train number,train timetable and train route are also summarized,and four common train routings are introduced to lay the theoretical foundation for the next study.(2)Secondly,the relationship between the spread of epidemic and the risk of passenger infection was carefully introduced,and the two key indicators for evaluating the risk were the full occupancy rate of train cars and the density of passenger seats,and the threshold values were set to classify the risk level of passengers in the train cars to build the evaluation index of the risk of epidemic spread,which provided the basis for the subsequent modeling.(3)Then,the epidemic transmission risk evaluation index is formulated and a model with the objective of minimizing the cost of train operation and the epidemic transmission risk of trains is established,considering constraints such as the number of train operations,train route and service coupling,train timetable,and passenger loading process.Due to the existence of some nonlinear constraints,they are linearized by inducing reasoning and finally built as a mixed integer linear programming model,while a degenerate model considering only timetable is also proposed.Due to the huge scale of the model,a combined algorithm combining simulated annealing heuristic(SA)and CPLEX solution is developed.(4)Finally,Nanchang Metro Line 2 is selected as a case study for validation.This metro line has obvious characteristics of huge and small passenger flow segments,and then the opening scheme and schedule of this line are optimized.The results of the study show that the proposed optimized scheme only reduces the risk by 6.75% compared with the scheme considering only the timetable,but compared with the original scheme,the risk can be reduced by 25.3% with only 5.78% increase in the running cost,and the optimized scheme can reduce the risk of epidemic transmission in the carriage to a greater extent.Next,the target weights are analyzed,and the cost of operation and risk can be better than the original scheme at the same time with specific weight values.Therefore,in actual operation,metro operators can flexibly adjust the operation scheme according to the target focus.