Using Simple Simulation Models in Operational Analysis of Rail Transit Lines: Case Study of Boston’s Red Line

This paper explores the operational performance of the Massachusetts Bay Transportation Authority (MBTA) Red Line, a conventional heavy rail line, using a simple computer simulation model developed specifically for this purpose. The model incorporates most of the important variables that affect performance, including the signal system, passenger flow, the train station dwell time, and realistic train and operator behavior. The model was used to analyze the minimum achievable headway on the line and to examine whether a reduction in the scheduled number of trains operating in the peak period could be made without negatively affecting service quality. Experiments with the simulation model demonstrated that MBTA could indeed reduce the number of trains operating in the evening peak period without degrading service quality. Based on these results, MBTA implemented a new timetable that reduced operational costs at the same time as reducing train delays on the line, without any significant negative effects on passenger service.