The first metro train for Line 18 of the Grand Paris Express has been officially unveiled following its delivery to the Palaiseau operations centre, marking the beginning of testing on the new automated line. The milestone was announced on 17 June 2025 by the Société des grands projets, Île-de-France Mobilités, and Alstom.
Delivered in May on schedule, the trainset’s arrival signals the start of dynamic testing ahead of the planned launch of the initial section between Massy – Palaiseau and Christ de Saclay in late 2026.
Grand Paris Express Line 18: Train delivery ahead of commissioning
Île-de-France Mobilités has financed a total of 15 trainsets for Line 18, at a cost of EUR 199 million. These trains are being delivered to the Palaiseau site and will support two phases of operation: ten units will serve the first segment from Massy – Palaiseau to Christ de Saclay, while five additional trains will support the southern extension to Orly Airport, scheduled to open by the end of 2027.
Testing phase underway
The entry into testing marks a crucial step in the delivery of Line 18. Static and dynamic tests have already been conducted at Alstom’s Valenciennes facility and the Centre d’Essais Ferroviaires. With delivery to Palaiseau complete, testing has now shifted to the actual infrastructure.
Initial “static” tests began in June, involving the energisation of the tracks and verification of onboard systems at the depot. All trials will be coordinated from the newly completed central control centre in Palaiseau, where Alstom has installed line supervision systems. Alstom will continue to oversee testing until operational responsibility is transferred to Keolis, the operator appointed by Île-de-France Mobilités.
By the end of 2025, ten trainsets will have been delivered to enable “dynamic” tests across the full 8.5 km stretch of completed track. These tests will verify the interaction between the train and infrastructure, including platform edge doors, communication systems, and signalling.
Train features
Line 18’s rolling stock has been specifically designed for the new automated line. Each three-car train is 47 metres long, 2.5 metres wide, and can carry up to 350 passengers. Designed and built by Alstom at its Valenciennes facility with support from five other sites across France, the trains integrate passenger comfort, accessibility, and advanced technology.
Key interior features include:
- Large windows and ambient under-seat lighting for optimal brightness
- Ergonomically designed seating
- Low-floor access, wide doors, and dedicated space for wheelchair users
- USB ports, real-time information displays, and intelligent air-conditioning
The exterior design, chosen through a public consultation conducted by Île-de-France Mobilités in late 2021, features a panoramic windscreen framed by a luminous “diamond” signature. This distinctive styling improves visibility and enhances onboard space.
A key link in the Grand Paris Express
When fully complete, Line 18 will span 33 kilometres, linking ten new stations, three of which will be elevated. The route will connect key destinations in the Île-de-France region, including Antony, Massy, the Saclay plateau, Saint-Quentin-en-Yvelines, and Versailles.
The line will offer strong multimodal connections with several existing services, including:
- Metro line 14 at Orly Airport
- RER lines B and C
- Tramway line T7
- Tram-train line T12
- Train lines N and U
Line 18 is designed to serve the growing travel demands of local residents, students, and workers across major academic and research hubs.
Automation and energy efficiency
As a 100% automated and electric metro line, Line 18 promises high-frequency service with a train every 90 seconds during peak hours. Operating at an average speed of 65 km/h, trains will be capable of reaching 100 km/h.
Environmental performance is a core element of the project. The system will recover braking energy to reduce power consumption. Uniquely within the Île-de-France network, Line 18 will use a ground-level third rail with reverse collection to power the trains at 1,500 V, eliminating the need for overhead lines and preserving the visual landscape along elevated sections.
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