tramsecs

tramsecs is a specialized unit of time measurement used primarily in the planning and operation of tram networks in certain European cities. One tramsec equals 0.02 of a second, or 20 milliseconds. The concept was introduced in the early 1990s by the Tramway Performance Group (TPG) to address the need for finer granularity in timetabling than the conventional second allowed.

In practice, tramsecs are embedded in timetable files, signalling control protocols, and passenger information systems. By dividing a full second into fifty smaller increments, planners can schedule interarrival times in 20‑millisecond steps, enabling smoother headway adjustments during peak periods. The metric is also useful in real‑time monitoring; sensor data from tram doors, axle counters, and GPS units are aggregated into tramsec slices to detect delays, track maintenance requirements, and validate service levels.

The unit remained largely confined to the member cities of the TPG—such as Munich, Oslo, and Stuttgart—where high-frequency tram services demand rapid, precise control. International adoption has been limited by the need for compatible hardware and software that can process tramsec‑based time stamps. Nevertheless, several research studies have cited tramsecs as a model for high‑frequency transit scheduling, and the concept continues to influence developments in next‑generation tram control systems.