Commuter rail

Commuter rail or suburban rail is a passenger rail service that primarily operates within a metropolitan area, connecting the central city to its suburbs and commuter towns. Commuter rail systems can use locomotive-hauled trains or multiple units, using electric or diesel propulsion. Distance charges or zone pricing may be used. The term can refer to systems with a wide variety of different features and service frequencies, but typically refers to mainline rail services connecting suburban communities with central business districts over medium distances; it is distinguished from rapid transit systems, which operate inside the urban core. Some services blur the line between suburban rail and rapid transit; examples include German S-Bahn in some cities, the Réseau Express Régional (RER) in Paris, the S Lines in Milan, many Japanese commuter systems, the East Rail line in Hong Kong, and some Australasian suburban networks, such as Sydney Trains and Metro Trains Melbourne. Many commuter rail systems share tracks with other passenger services and freight. In North America, commuter rail sometimes refers only to systems that primarily operate during rush hour and offer little to no service for the rest of the day, with regional rail being used to refer to systems that offer all-day service.