Analysis On The Train Routing Scheme Of Y-type Urban Rail Line

With the advantages of great capacity,high efficiency and low energy consumption,urban rail transit has become the first choice to establish an efficient,fast and green urban transportation system.With the expansion of urban rail transit network in China,the area that urban rail transit covers extends from central city to suburb,inspiring a suburban passenger flow with obvious dispersion characteristics.The Y-type lines achieve the goal of expanding the covering area and saving the construction investment by connecting branch to trunk.How to meet the demand of dispersal passenger travel and equilibrate the occupation of main lines and branch lines has become an important issue of operation management of urban rail transit system with Y-type lines.Urban rail transit management aims at two targets which are to improve the service level and to reduce the operating costs.For Y-type lines,it has become a significant issue about how to formulate a reasonable train routing scheme to meet the demand of passengers while tapping the potential of the capacity at the same time through the reasonable deployment of the existing transport capacity.Based on the existing research results,the main contents and conclusions of the dissertation are shown as follows.The dissertation analyzes the background,features,forms of train routing and factors that influence the design of the train routing scheme of Y-type lines.The dissertation compares routing schemes of Y-type lines between the ones abroad and nationwide,providing a theoretical basis and practical basis for designing train routing schemes of Y-type line.Taking the minimum passenger travel time and the minimum train operating distance as the objective function,the dissertation establishes an optimization model for the train routing scheme for Y-type lines,with a consideration of constraints about the train load,the minimum train tracking interval,the turn-back capacity of the stations,the minimum frequency and the number of vehicles.Taking a T-type line in City S as a case,the dissertation gets the optimal train routing scheme with genetic algorithm to solve the optimization model of the train routing scheme for Y-type lines.The results show that:train operating.distance decreases first and then increases,while passenger travel time,passengers waiting time,passengers transfer time,the number of transfer passengers,the average load rate and maximum load rate all decreases with the increasing of the weight valve of the passenger travel time,The dissertation compares the optimal train routing scheme,the train routing scheme that the branches are all on separate operation and the train routing scheme that the branches have fully straight-through operation.The result show that:passenger travel time and passenger waiting time all increase from the optimal train routing scheme to the train routing scheme that the branches are all on separate operation while the train operating distance,passenger transfer time,average passenger transfer time,the number of transfer passengers,passenger waiting time of the branches decrease.Therefore,the train routing scheme that the branches are all on separate operation is beneficial to the trunk passengers and detrimental to the branch passengers.On the other hand,passenger travel time,passenger waiting time,passenger transfer time all increase from the optimal train routing scheme to the train routing scheme that the branches are all on fully straight-through operation,while passenger waiting time and average load rate of the branches decrease,train operating distance also decreases.Therefore,the operation enterprises cannot just simply choose the fully straight-through operation scheme,they shall determine the location of the turn-back station reasonably according to the characteristics of passenger flow and realize system optimizationFinally,the dissertation analyzes the influence of the upper bound of the train load rate and the location of the turn-back station of the branch.The influence of the upper bound of the train load rate shows that the variation of the index is significantly different from the variation of the train load rate when the weight value is vary.The dissertation analyzes the influence on the train routing scheme with different locations of turn-back stations.Assumed that there are two branches operated in the system,one is on separate operation while the other is on straight-through,the simulation result shows that the index changes in different ’tendency when different adjustment strategies are applied.One strategy is changing the location of the separate-operation branch’s turn-back when the location of the straight-through branch’s turn-back station is fixed.The other strategy is changing the location of the straight-through branch’s turn-back when the location of the separate-operation branch’s turn-back station is fixed.The result is remarkable.