The extension was initially served by a limited shuttle service between Nanterre and Magenta that operated only outside peak hours.

[10] It will be located north of Chemin des Boutareines, near the bridge over which the future Altival exclusive right-of-way bus will cross the RER E tracks.

The station's location is a complicated issue, as there are currently only two tracks (between Les Boullereaux and Villiers - Le Plessis-Trévise) at this point, where many trains cross each other.

[14] Initial studies carried out by Réseau ferré de France (RFF) in conjunction with Société du Grand Paris (SGP) show that the additional stops for all trains on the line, as well as any Transilien Line P services at the station, would require a four-track upgrade between Villiers-Champigny-Bry and Villiers-sur-Marne, at an estimated cost of €200 million at 2010 economic conditions, excluding the cost of constructing the passenger building.

[20] On May 19, 2010, SNCF CEO Guillaume Pepy and local elected representatives visited the Val Bréon site, where the new eastern terminus is to be built, the possibility of extending the line to Marles-en-Brie having been ruled out.

"[22] The project involves extending the RER E line from Tournan station to Val Bréon, one of the largest logistics centers in the Île-de-France.

This extension would make it possible to create a service in line with the development of this area, which is only accessible by car and where the number of employees could increase, as well as resolving the RER line's operating difficulties by creating a new site for parking trains[22] and relieving the Gretz-Armainvilliers and Tournan stations of cars arriving from the east of the département: "According to the mayor of Tournan-en-Brie:[21] "The outskirts of the town are clogged: cars arrive in the morning and leave again in the evening, a daily problem for locals.

The current terminus attracts passengers from a radius of around 50 km (31 mi), taking advantage of the fact that RER E runs to the center of Paris.

[22] Vincent Eblé acknowledges at least one weakness in this project: "The Val Bréon area is not easily accessible by public transport.

[21] However, studies carried out as part of the sector plan showed that, given the traffic constraints on the whole of Transilien Line P (between Paris and Tournan-en-Brie), the nine trains (in both directions) that could run per peak hour between Tournan and Val Bréon would require doubling the track on this section of the line, at an estimated cost of around €100 million at 2010 economic conditions.

[15] The eastward extension of branch E2, which currently terminates at Chelles-Gournay station, to Meaux station, with intermediate stops at Vaires–Torcy, Lagny–Thorigny, and Esbly, is included in Phase 3 (2021-2027) of the Schéma directeur de la région Île-de-France (SDRIF), adopted by deliberation of the Regional Council of Île-de-France on 25 September 2008.

Extending RER E to Meaux would provide better service to this town, which, with over 50,000 inhabitants, is the most densely populated in the department of Seine-et-Marne.

This project would improve service to the north of the department, particularly the new town of Marne-la-Vallée, with a second significant public transport line to complement RER A.

It would give users of the current Meaux terminus link from Paris (Transilien Line P) direct access to the Magenta, Haussmann–Saint-Lazare, Porte Maillot and La Défense transfer hubs.

On the other hand, depending on the number of stops, the RER E service could take longer to reach Paris than Line P trains.

However, the sector plan studies highlighted that mixing RER E and Transport express régional (TER) traffic between Chelles (or Lagny with additional tracks) and Meaux would be a source of conflict, and that access to the RER E tunnel without connections would not result in a gain in journey time between Meaux and Haussmann (estimated at 42 minutes by direct train).

Finally, they highlighted that creating a pedestrian link between Gare de l'Est and Gare du Nord would significantly facilitate connections between Line P and RER E. As a result, STIF (now Île-de-France Mobilités) was planning to carry out further studies to assess the benefits of creating a pedestrian link.