Peruslinja

Peruslinja is a Finnish term used in public transport planning to denote the backbone or core routes of a transit network. The concept describes lines that are designed to provide high-frequency, all-day service and to connect major destinations such as city centers, railway stations, large employment centers, universities, hospitals, and densely populated suburbs. As the backbone of the timetable, peruslinjat typically offer broad geographic coverage and serve as the main arteries through which passengers travel long distances within the network.

In planning practice, peruslinjat are complemented by feeder, connector, and local services that extend coverage to areas not directly served by the base lines. The aim is to ensure that most passengers can access a peruslinja within a reasonable distance and transfer once or twice to reach their final destination. Operationally, peruslinjat usually have the highest service levels, with increased frequency and longer operating hours compared to secondary lines, while reliability and punctuality are prioritized to maintain a stable network image.

The term originates from Finnish transport planning discourse and is widely understood among operators and planners in Finland. Its precise use can vary by city or region, but the underlying idea is to simplify timetable communication and to anchor service planning around a set of essential routes that handle the bulk of passenger demand, forming the durable core of the public transport system.