Grand Paris Express: Line 15 South delayed again, Line 18 to open in December

The much-anticipated southern section of Line 15 of the Grand Paris Express, a major public transport project, will face further delays, pushing its opening back by several months. This postponement affects one of the most eagerly awaited segments of the new automated suburban metro.

In contrast, the first section of Line 18, connecting Massy - Palaiseau to the Plateau de Saclay, is set to open sooner than expected. The Société des grands projets (SGP) announced that this segment will be operational starting November 30, 2026. While this represents a slight delay from an earlier October target, the line will be ready for passengers in the first week of December after technical transfer and testing phases.

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Difficulties have been encountered in the pace of deploying transport automation equipment in tunnels, which condition the engagement of system testing phases.

However, the outlook for Line 15 Sud remains uncertain. Originally slated for completion by the end of 2026 and later rescheduled for April 2027, its opening is now projected for autumn 2027. The SGP cited "significant progress" in testing but indicated that the implementation plan is taking longer than anticipated.

The SGP explained that the delays stem from the sheer scale of the project, with the southern section alone spanning over 30 kilometers. Specific challenges include the pace of deploying automation systems within the tunnels, which are crucial for initiating system testing. Additionally, the integration of the 16 stations and their associated equipment has proven to be a complex process, impacting the project's timeline.

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Similarly, the pace of integration of the 16 stations and all the equipment that comprises them, a complex process and requiring strong mobilization of the holders on the critical path of the project, is no longer consistent with the objective of April 2027.