Paris and Île-de-France public transport is in constant flux. As the MF19 is gradually rolled out across several metro lines, travelers will soon get to explore four new lines of the Grand Paris Express, namely lines 15, 16, 17 and 18.
Until then, all eyes will be on the RER E and its new western extension. After a first expansion to Nanterre-La-Folie in 2024, the RER E will be extended again to Mantes-la-Jolie this time — slated as the terminus and final milestone of the EOLE project (Est-Ouest Liaison Express). After years of waiting, commuters will finally be able to use the RER E to reach Mantes-la-Jolie starting February 28, 2027. The rollout will be gradual, with full capacity expected by late 2029, or perhaps early 2030.
RER E: Official start date announced for the extension to Mantes-la-Jolie
The first major milestone of the EOLE project was marked in 2024 with the extension of the RER E to Nanterre-la-Folie in Hauts-de-Seine. Now all eyes are on the second phase of the extension, this time in the Yvelines. So, when is the final extension slated to go into service? When will travelers be able to board the RER E to reach Mantes-la-Jolie? Here’s what we know. [Read more]
The extension of the RER E to Mantes-la-Jolie is intended, among other things, to relieve the heavily used RER A at rush hours, and also to shorten travel times, notably by directly linking Mantes-la-Jolie to La Défense in around 40 minutes.
The EOLE project nevertheless raises several questions, namely: will the RER E eventually replace the J5 line? The answer is yes, as Eole states on its website.
Note that the Line J of the Transilien network is made up of several branches serving different areas from Paris Saint-Lazare. Notably the J4 branch between Paris Saint-Lazare and Ermont-Eaubonne, the J6 which reaches Mantes-la-Jolie via Conflans-Sainte-Honorine / Gisors from Paris Saint-Lazare, and also the J5 which links Paris Saint-Lazare to Mantes-la-Jolie via Poissy. The J5 branch serves notably Houilles-Carrières-sur-Seine, Poissy, Villennes-sur-Seine, Vernouillet-Verneuil, Les Clairières de Verneuil, Les Mureaux, Aubergenville-Élisabethville, Épône-Mézières, Mantes-Station and Mantes-la-Jolie. These 10 stations along the Seine valley are precisely the 10 new stations listed on the route of the extension of the RER E.
The consequence? With the full opening of its extension, the RER E will officially and completely assume control of the Mantes-la-Jolie / Poissy axis, currently operated by Transilien Line J. The J5 branch of Line J as we know it today is set to disappear, replaced by the RER E.
RER E: Official start date announced for the extension to Mantes-la-Jolie
