RER C: €8bn Tender Launched for 300 New Z2N NG Double-Deck EMUs

SNCF Voyageurs and Île-de-France Mobilités have jointly issued a framework tender for up to 300 next-generation double-deck electric multiple units, designated Z2N NG.

The contract, running for a maximum of 23 years with a total potential value of €8 billion, includes a firm initial order for 52 units worth €1.5 billion — the largest rolling stock renewal programme ever launched for the Paris RER C commuter line.

A Framework Contract Worth Up to €8 Billion

The agreement is structured around five components. The firm tranche covers 52 trains (€1.5 billion) earmarked for the future Line Y service [to be confirmed]. Four options complete the framework: Option 1 adds 198 further trains primarily for Line C (€4.1 billion); Option 2 provides maintenance and logistics support for Île-de-France Mobilités (€1.2 billion); Option 3 covers 50 trains for SNCF (€986 million); Option 4 covers SNCF maintenance (€245 million).

The average unit cost works out to approximately €26.7 million per train — a marked increase compared with previous orders. By comparison, the 2017 RER NG contract (Z 58000/Z 58500 series) covered 255 trains for €3.75 billion, roughly €14.7 million per unit. The difference reflects raw material inflation, updated accessibility standards, and more demanding technical requirements.

Tailored to Line C's Unique Constraints

The functional requirements document published by Île-de-France Mobilités in late 2024 sets out strict parameters. The Z2N NG must comply with the FR3.3 loading gauge — compatible with double-deck architecture — while not exceeding 105 metres in length to fit existing platforms on Line C. The boarding floor will be set at 550 mm above rail level, compared with 970–1,000 mm on the current RER NG fleet, greatly improving step-free access for passengers with reduced mobility.

Minimum seating capacity is set at 455 passengers, with an optimal target of 500. The trains will adopt a "boa" open-gangway design allowing free passenger flow throughout the entire length of the unit. An on-board energy storage system will also be fitted, supplementing catenary power and reducing the need for costly electrical infrastructure upgrades along the line.

The line's central underground section — the tunnel between Paris-Austerlitz and Invalides — is not currently compatible with the FR3.3 gauge. Infrastructure adaptation works are estimated at €1.5 billion [to be confirmed], a cost the French state has yet to commit to funding.

Line Y: First Service Planned for 2032

The 52 firm-order trains are intended for the future Line Y [to be confirmed], a new Transilien service linking Paris-Austerlitz with Dourdan and Saint-Martin-d'Étampes. First service is announced for 2032 [to be confirmed]. Both branches are the southernmost sections of the RER C network, operated at surface level and therefore unaffected by the gauge incompatibility in the Paris tunnel.

The arrival of the Z2N NG will allow the gradual retirement of the oldest rolling stock still serving Line C: the Z 5600 class (built 1983–1985), Z 8800 (1986–1988), Z 20500 (1988–1997), and Z 20900 (2001–2003). As an interim measure, Z 20500 units freed up by Line D — which began receiving the new RER NG (Z 58500) in December 2024 — have been cascaded onto Line C since February 2025.

Contract Framework Summary