TIMETABLE SYNCHRONIZATION FOR MASS TRANSIT RAILWAYS

In most urban public transport systems, passengers may need to make several interchanges between different lines to get to their destination. Designing timetables that enable smooth interchanges with minimal delay for all passengers is a service goal of the MTR Corporation Limited (MTRCL), which runs six railway lines with many cross-platform interchange stations within the Mass Transit Railway (MTR) system in Hong Kong. Designing such co-ordinated timetables is a very difficult task. This paper describes a set of decision-support tools for this timetable synchronization problem. The core of the system is a mixed-integer-programming (MIP) optimization model that minimizes the interchange waiting-times of all passengers. A novelty in our formulation is the use of binary variables which enable the correct representation of the waiting-times for transfer to the “next available” train at the interchange stations. By adjusting the trains’ run-times and station dwell-times during their trips, and their dispatch times, turnaround times and headways at the terminals, our system can construct highquality timetables that optimize the objective of minimizing passenger transfer waiting-times. We have tested our system for rush-hour and non-rush hour periods. Preliminary numerical results indicate that our approach improves the synchronization compared to current practice significantly. We also explore the trade-offs among different operational parameters and flexibility and the impact on overall passenger waiting-times. The preliminary results are very encouraging.