Train Scheduling And Delay Analysis Of Urban Rail Transit Based On Dwell Time Model

ABSTRACT:With the growth of urban population, traffic demand has gradually increased in China. Urban rail transit has become an important part of urban public transportation with the advantages of safety and high efficiency, convenience and reliability, low energy consumption and light environmental pollution. The basic purpose of urban rail transit is to service for passengers and train operation is highly affected by the variation of passenger flow. The passengers on-off has a direct impact on the dwell time. Due to the variation of the passengers on-off, the delay of the train will be caused. Hence, the optimization of train scheduling as well as the research about the train delay based on the relationship between passengers and trains have become important research issues in the field of urban rail transportation. Scholars are attracted by the issues with the development of urban rail transit system. Considering the dwell time model, the optimization of train scheduling and the analysis of train delay are discussed as follows:Firstly, the optimization of train scheduling based on dwell time model is studied. A mathematical model of train schedule is established, with the constraints of headway, passenger, and dwell time model, where the train dwell time is modeled as a function of the passenger boarding and alighting volumes. The aim of the optimization problem is to minimize the waiting time of passengers and the number of trains in service directly or indirectly. Lagrangian duality theory, suited to the high dimensionality of NP problem, is adopted to solve this optimization problem. Simulation results demonstrate that this method is efficient to generate the train schedules, which meets the passengers exchanging requirements between trains and platforms.Secondly, the direct delay to trains, the knock-on delay to other trains and the calculation models of delay with different adjustment strategy are studied. The definition of train delay and the factors are analyzed. And the dwell time model is applied to delay calculation. The direct delay and knock-on delay calculation models are established. At the same time, two delay adjustment strategies are proposed. One adjusts interval time and the other adjusts interval time and the headway. New knock-on delay models based on adjust strategies are established.Finally, according to the train delay method and the generation of train scheduling, train delay calculation software is developed and the adjustment strategies are evaluated with the rules. The software is designed based on the.NET Framework. The simulation software contains three function modules, the train diagram generation, the delay calculation and the evaluation of delay adjustment strategy. The delay evaluation functions are established, and direct delay and knock-on delay are calculated. The advantages and disadvantages of different delay adjustment strategies are evaluated with the same delay experiment.