page_title: RER E
section_title: Extension
hierarchical_section_title: RER E / Extension
caption_attribution_description: Français&#160;: Prolongement à l'ouest du RER E
context_page_description: RER E is one of the five lines in the Réseau Express Régional, a hybrid suburban commuter/rapid transit system serving Paris, France and its suburbs. The 52.3 km RER E line travels between Paris and eastern suburbs, with all trains serving the stations in central Paris, before branching out towards the ends of the line.
  The line runs from the western terminus Haussmann–Saint-Lazare to the eastern termini Chelles–Gournay and Tournan. It is operated by SNCF.
  Originally referred to as the Est Ouest Liaison Express or EOLE, RER E is the newest line in the system opening in 1999, with the extension in 2003, and further extensions to the west currently under construction.
context_section_description: RER E is to be extended from Haussmann – Saint-Lazare to La Défense, from where it will take over the branch of RER A to Nanterre, Sartrouville and Poissy. It would then take over a section of SNCF tracks (currently carrying Transilien J) to reach Mantes-la-Jolie. Partial revenue service is expected to begin in 2022, full service in 2024.
  An eight kilometre tunnel will be dug between Haussmann–St-Lazare and La Défense. An intermediate station at Porte Maillot will offer a transfer to RER C. The extension is expected to reduce the load on central sections of RER B (between Gare du Nord and Châtelet) and RER A (between La Défense and Auber) by 10-15%. Additionally, transfers will be shifted away from current transfer hub Châtelet.
caption: Map of the extension to Mantes-la-Jolie
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