Technical setbacks delay Grand Paris Express line 18 opening beyond 2026
The handover of line 18 to Ile-de-France Mobilités has stalled as IDFM, RATP and Keolis deem the system not ready for the final two-month test phase.
On the recent transfer of technical management, the Société des grands projets handed over line 18 to its new owner, Ile-de-France Mobilités. IDFM, the infrastructure operator RATP and the future operator Keolis all declined to start the two-month "marche à blanc" because they judged the reliability and safety conditions inadequate. The bottleneck is the line’s automation system, built by Alstom, which must coordinate train movements and station equipment and was found to be far more complex than anticipated.
Lines 15, 16 and 17 face comparable delays, though their systems were supplied by Siemens. Unless a solution is found imminently, the line will miss the planned 2026 opening. Valérie Pécresse, president of the Ile-de-France region, said the responsibility lies with Alstom and the Société des grands projets.
Why it matters
The postponement pushes back a key transit project that will shape mobility for millions in the Paris region.
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