Réseau Express Régional

The Réseau Express Régional , colloquially called the RER , is a hybrid suburban commuter/rapid transit system serving Paris, France and its suburbs. The RER combines the operations and roles of a local city centre underground rail system and suburbs to city center commuter rail. Inside the city center, the RER functions much like the Métro, but is faster as it has fewer stops. This has made it a model for proposals to improve transit within other cities. The network consists of five lines: A, B, C, D and E. The network has 258 stations and has several connections with the Paris Métro within the city of Paris. The lines are identified by letters to avoid confusion with the Métro lines, which are identified by numbers. The RER is still expanding: Line E, which opened in 1999, is planned for westward extension in two phases by 2020–2022.
The RER contains 257 stations, 33 of which are within the city of Paris, and runs over 587 km of track, including 76.5 km underground. Each line passes through the city almost exclusively underground and on dedicated tracks. The RER is operated partly by RATP, the transport authority that operates most public transportation in Paris, and partly by SNCF, the national rail operator. In spite of this, the system uses a single fare structure and no transfer is needed between sections run by the two operators. Total traffic on the central sections of lines A and B, operated by RATP, was 452 million people in 2006; in the same year, total traffic on all lines operated by SNCF was 657 million.

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