Addressing metro line disruptions through boarding limits : The cost and time of system recovery

A mathematical programming model is applied to regulate service supply and demand on a high-frequency metro-type rail transit system under disruptive events and congestion. The approach implements the boarding limit strategy in addition to train holding and speed control while minimizing user costs and energy consumption. Simulations of scenarios involving different disruption durations show that boarding limits generate increasingly significant reductions in negative impacts as the durations lengthen. The incorporation of social cost and system recovery measures allows the proposed methodology also to be used as a tool for system control decision-making. In particular, it can determine the point at which boarding limits become beneficial, which in the simulations was estimated to occur when disruptions are two times the headways at high-demand levels.