Study On The Optimum Combinational Operation Scheme Of Urban Rail Transit Express-Local Trains And Cross-Line Operation

With the development of large cities and urban agglomerations in China,regional rapid rail transit networks between urban areas and urban agglomerations are being planned and constructed on a large scale.In order to shorten the travel time of commuter passengers and improve the utilization rate of trains,express-local trains and cross-line operation modes are widely used in rapid rail transit lines.Most of the metro lines built in urban centers in China operate independently on a single line,so the research on express-local trains and cross-line operation is still in its infancy.Based on the analysis of the interaction mechanism and operation organization technology between express-local trains and cross-line operation,this paper puts forward the calculation model of the combined operation optimization scheme of the two lines.The main research contents and achievements are as follows:(1)On the basis of theoretical research and quantitative calculation on the operation mode of express-local trains in urban rail transit,the influence of operating express-local trains on the line passing capacity and the reasonable stopping scheme of express-local trains,the paper puts forward the line running density,passing capacity,the selection of overtaking stations and the criteria for determining overtaking of express-local trains.(2)Taking the travel time of passengers crossing the metro line as the goal,according to the minimum interval between the two lines and the transfer time of passengers on the two lines,the conditions for running trains crossing the metro line under different traffic densities are calculated.(3)Based on the passenger's selection and transfer behavior in express-local trains'workshops,the express trains crossing to metro line and their turn-back stations,the passengers are divided into three categories:local trains on regional lines,express trains across lines and trains on metro lines.According to the train operation schedule,the minimum total travel time of all passengers and the total number of trains used are taken as the dual objectives,and the constraints of various train tracking intervals and train density are taken as the constraints.The departure ratio of express-local train,operation mode of cross-line trains(insertion and substitution),express train stopping station,overtaking station and turn-back station are taken as the decision variables.The optimization model of combined operation scheme of express-local train and cross-line is established,and the solving algorithm is compiled based on python.(4)Taking Chongqing Jiangjin line and metro line 5 as an example,the case is solved by using the established combined operation optimization model.The optimal combined operation scheme is as follows:the frequency of Jiangjin line departure is 12 rows/h,the ratio of express-local train departure is 1:1,the express train runs non-stop at 6th,7th,8th,9th and 10th station,and overtakes at 8th station;the departure frequency of line 5 is 18 rows/h,and the crossing express train turns back at 32 stations.Compared with the stop by stop and independent operation schemes of existing operation scheme,the passenger travel time and the total number of trains used in the optimized scheme are reduced by 8.49%and 7.69%respectively.On this basis,the sensitivity analysis of five factors affecting the combined operation scheme is carried out.The results show that under the same conditions,the substitution mode is better than the insertion mode,the total travel time of passengers increases by 1.22%,but the number of trains used decreases by 18.33%;the 1:1 express-local train scheme is better than the the 2:1 express-local train scheme,the total travel time of passengers increases by 0.46%,but the number of trains used decreases by 3.33%;compared with other full load rate scenarios,the combination scheme with full load rate of 0.8 is the best;under the feasible station dwell time and the minimum train tracking interval,the longer the station dwell time and the smaller the minimum tracking interval are,the better the express-local train scheme is compared with the stop-by-stop scheme.