Although the Société des Grands Projets handed over the keys to Line 18 of the Grand Paris Express to Île-de-France Mobilités (IDFM) on October 13, its opening was postponed to mid-December or even 2027.
Indeed, the initial tests of the trains did not meet the expectations of the three partners, IDFM, RATP GI, the infrastructure manager, and Keolis, the operator that will provide passenger transport. Developed by the manufacturer Alstom, the system of driverless automated trains is at the heart of the technical concerns.
A 30-minute connection to link the Orly airport to Versailles by 2030
This first section of line 18 will connect the Massy-Palaiseau station to three stations: Polytechnique, Université Paris-Saclay and Christ de Saclay. It will thus serve the Saclay plateau, which is home to higher education institutions, research laboratories and innovative companies. Beyond the residents of the area, this new service will also facilitate the daily commuting of students, teachers, researchers, engineers, technicians and employees who work in the institutions and companies of this region.
A particularity of this section of the line is that it features the longest viaduct in France, which stretches over 6.7 km to cross the main road infrastructure while promoting better landscape integration.
In the long term, line 18 will connect Paris-Orly Airport to Versailles-Chantiers in 30 minutes on a route that includes 10 stations. With trains that can carry up to 350 passengers and a frequency of every 3 minutes during peak hours, connections will be facilitated with the line 14 in Orly (autumn 2027), the RER B and C lines, the T12 tramway and the TGV station in Massy-Palaiseau, as well as with the RER C and the TER and Transilien N, U and V lines in Versailles-Chantiers (in 2030).
The Grand Paris Express now completed by 2031
The Société des Grands Projets also recently reviewed the schedule for the commissioning of the other lines 15, 16 and 17 of the Grand Paris Express. Again, the complexity of the development and validation of the automation systems explains part of the delays announced.
The Grand Paris Express, which envisages the creation of 200 km of automated lines and 68 new stations, should now be completed only by 2031.
The opening of line 15 Sud, between Pont de Sèvres and Noisy-Champs, with its 16 stations, is now scheduled for autumn 2027.
In 2028, two first sections will enter service from Saint-Denis Pleyel: line 16 to Parc du Blanc-Mesnil and line 17 to the Bourget airport. They will then be extended in the autumn of 2029: line 16 to Noisy-Champs, while line 17 will reach the Villepinte Exhibition Centre.
In 2030, line 17 will continue its journey to Mesnil-Amelot, passing through Paris-Charles-de-Gaulle Airport. This extension will be an essential link for travelers and the tens of thousands of employees of the Parisian airport platform.
Finally, the year 2031 will mark the completion of line 15, with the commissioning of its two branches: to the west, between Pont de Sèvres and Saint-Denis Pleyel, and to the east, between Saint-Denis Pleyel and Champigny Centre.
To date, only line 14 is fully operational on its entire route, between Saint-Denis Pleyel and Orly Airport.
Launched more than ten years ago, the Grand Paris Express project has undergone several schedule revisions and an explosion in its budget. Its initial cost estimated in 2010 at 19 billion euros now amounts to 36 billion euros. A considerable investment but useful for facilitating travel in Île-de-France.
