Metro Service Delay Recovery: Comparison of Strategies and Constraints Across Systems

Document Type

Journal Article

Publication Date


Subject Area

operations - traffic, planning - service quality, land use - planning, mode - rail, mode - subway/metro


Transit operators, Traffic delay, Strategies, Strategic planning, Service restoration, Service quality, Rail transit, Quality of service, Priorities, Performance, Passenger service quality, Optimization, Optimisation, On time performance, Objectives, Level of service, Goals, Constraints, Case studies


This study was conducted to identify the strategies used by operators to provide a high level of service. The research distinguishes between punctuality and regularity of service and proposes that metro passengers primarily value regularity. The focus of this research is not on incident prevention, but on strategies that can be implemented after an incident to restore service swiftly and to minimize delay. The research identifies the recovery strategies used by six metros and summarizes advantages and disadvantages of these strategies. The influence of the type of delay on the choice of strategy is described. Similarly, the impact of constraints such as line length, service frequency, and passenger crowding on the effectiveness of each strategy is also discussed. It was found that it was generally sufficient to distinguish minor incidents, slow-moving delays, and major incidents. A case study shows that those metros with higher inbuilt flexibility can return more easily to normal service. This finding will have implications for metro management. The research has been carried out by the Railway Technology Strategy Centre at Imperial College London in collaboration with the Community of Metros benchmarking group. The performances and service qualities of six metros (three European, two American, and one Asian) have been analyzed and compared. The study consists of a quantitative analysis of the performance of two lines from each metro, together with a more qualitative assessment of the strategies used to optimize performance, through structured interviews with key operational and managerial staff.