Commuter line

Commuter rail, also called suburban rail, is a passenger rail transport service that primarily operates between a city centre, and the middle to outer suburbs beyond 15 km (10 miles) and commuter towns or other locations that draw large numbers of commuters—people who travel on a daily basis. Trains operate following a schedule, at speeds varying from 50 to 200 km/h (30 to 125 mph). Distance charges or zone pricing may be used.

Non-English names include Treno suburbano in Italian, Cercanías in Spanish, Rodalies in Catalan, Proastiakos in Greek, S-Bahn in German (although Regionalbahn or stopping services occasionally also operate as commuter trains), Train de banlieue in French, Příměstský vlak or Esko in Czech, Elektrichka in Russian, Pociąg podmiejski in Polish and Pendeltåg in Swedish. The development of commuter rail services has become popular today, with the increased public awareness of congestion, dependence on fossil fuels, and other environmental issues, as well as the rising costs of owning, operating and parking automobiles.

Most commuter (or suburban) trains are built to main line rail standards, differing from light rail or rapid transit (metro rail) systems by:

Compared to rapid transit (or metro rail), commuter/suburban rail has lower frequency, following a schedule rather than fixed intervals, and fewer stations spaced further apart. They primarily serve lower density suburban areas (non inner-city), and often share right-of-way with intercity or freight trains. Some services operate only during peak hours and others uses fewer departures during off peak hours and weekends. Average speeds are high, often 50 km/h (30 mph) or higher. These higher speeds better serve the longer distances involved. Some services include express services which skip some stations in order to run faster and separate longer distance riders from short-distance ones.

...
Wikipedia