UIC Code 406 — Capacity (compression method)

Scope

Defines the UIC compression method for evaluating railway infrastructure capacity, in which real timetables are compressed to measure occupancy rates of lines and, since the 2nd edition, nodes. It gives infrastructure managers a uniform, internationally comparable methodology for capacity assessment, particularly on corridors spanning several networks.

UIC Code 406 defines the UIC compression method for evaluating railway infrastructure capacity, a methodology in which real, planned timetables for a given line or node are computationally 'compressed' -- trains are moved together in time as tightly as operationally and safety possible -- to measure the resulting occupancy rate as an indicator of how much spare capacity remains on that infrastructure. Since its 2nd edition, the method has been extended beyond simple line sections to also cover nodes such as junctions and station throat areas, where capacity constraints are often more complex than on plain double-track sections. It gives infrastructure managers a uniform, internationally comparable methodology for capacity assessment, which is particularly valuable on international corridors spanning the networks of several infrastructure managers, where each manager's own bespoke capacity assessment method would otherwise make cross-border comparison difficult. Capacity planners and infrastructure managers apply the compression method when assessing whether additional train paths can be accommodated on a given route or when justifying infrastructure investment based on demonstrated capacity constraints. The current edition is the 2nd Edition, published in 2013.