An Optimal Integrated Real-time Disruption Control Model for Rail Transit Systems

Abstract

Rail transit systems are subject to frequent minor disruptions caused by random disturbances. Although these minor disruptions usually last no longer than 10-20 minutes, they can degrade the level of service significantly on a short headway service. This paper describes an integrated real-time disruption control model, formulated as a mixed integer program, for rail transit systems, which includes holding, expressing and short-turning strategies. Although the model is capable of dealing with multi-branch systems, the model was applied to a disruption scenario on a single line system as a first step. Two cases with 10 and 20 minute disruption duration are tested. The results showed that holding strategies combined with short-turning strategies reduced the mean passenger waiting time by 35% in the former case and 57% in the latter case, compared with not applying any control strategies. Expressing provided only modest additional benefits. Sensitivity analysis was used to investigate the impact of the deterministic disruption duration assumption. The results showed that holding and expressing solutions were fairly robust, but the effectiveness of short-turning solutions was quite sensitive to the accuracy of the disruption duration estimate. In one scenario, the passenger waiting time increased by 14% under an estimate 50% less than the actual disruption duration, compared with the result with correct estimate. Problem instances without expressing can be solved in less than 30 seconds of computation time with the branch-and-bound algorithm proposed to solve this mixed integer problem.