How regular is a regular-interval timetable? From theory to application
Computers in Railways XII
Initially, choice of regular-interval timetable was mostly addressing operational concerns, aiming to increase the network throughput and to smooth the day-today tasks of the personnel. Separation between infrastructure management and train operations, induced by the European Union since the early 90s, and the future opening of the rail services to competition, pushes more and more infrastructure managers to operate their network with regular-interval timetable. Thus, the interest of measuring
... erest of measuring the degree of regularity. The paper defines the different steps needed for going from conventional operations to fully coordinated regular-interval timetable (the so-called clockface timetable). It starts by defining the basic notions, and shows some fundamental properties of regular-based timetables. Then, based on the definitions, a methodology is developed to measure and assess the regularity of a timetable, for a line and over a full-scale network. This is because, in practice, implementation of a perfectly regular timetable is not possible and, perhaps, neither desirable. Constraints related to demand or to resources lead to cancel train paths during off-peak periods or to provide extra stops or longer dwell times (and thus slowing down travel time) during peak hours, for instance. More specifically, the paper presents a methodology for determining the interval used to evaluate and compare reference and actual timetables, per train class and by corridors. Tolerances in measuring are dealt with. The developed methodology has been used to develop assessment software, which has been used in a real life application.