Train Rescheduling For An Urban Rail Transit Line Under Disruptions

With the rapid development of urban rail transit(URT)systems and the dramatically increase of passenger demand,the emergencies happen more and more in the daily operations due to the uncertain factors,such as failures of equipment.Hence,the passengers’ travel safety and efficiency are seriously affected.The flexibility of URT system is quite poor due to small headways between trains and limited infrastructures available.So once a disruption is occurred,a large number of passengers may be detained at stations in a short time interval,which will not only cause chaos in the operation of the line,but also impact the operation of the adjacent lines and even the whole urban railway network.This thesis studies the characteristics,classifications and handling processes of disruptions in an URT system.It is of great theoretical and practical significance to put forward rescheduling strategies to deal with various disruption scenarios.Firstly,conflicts detection for an URT line is carried out based on the blocking-time theory.The blocking time diagrams for the fixed block signaling system and moving block signaling system are analyzed,respectively.The conflict detection is performed at the main part of the line where trains are operated with moving block signaling system.In addition,the conflict detection is also performed at the turnaround stations(with crossover before/after the station)where trains are operated with fixed block signaling system.The minimum headway required for the conflict-free operation of trains is determined and can be used for the train scheduling and rescheduling process.Secondly,optimal operational headways for an URT line are studied based on the passenger flow data.In addition,an integrated train scheduling and rolling stock circulation model is formulated based on the optimal operational headways obtained by the passenger demand analysis.This integrated model takes the available infrastructure,rolling stocks,the turnaround capacity,etc.into account.The model obtained is nonlinear,which is transformed into a mixed integer linear programming(MILP)model by applying the transformation properties and is then solved by the branch-and-bound algorithm.The train schedule and rolling stock circulation plan are then optimized simultaneously.This research is the basis for train rescheduling under disruption scenarios.Finally,train rescheduling models and algorithms arc studied to maintain the transport capacity as much as possible under disruption scenarios with different characteristics.Based on the train rescheduling model under disruption,the adjustment of train operation plan and rolling stock circulation plan are optimized simultaneously according to the set-up of disruption scenarios.The effectiveness and feasibility of the proposed train rescheduling model and algorithms under disruptions are evaluated by using indicators such as stability,rolling stock utilization rate,etc.