The new MI20 train, which is due to enter service on the Paris RER B line by the end of 2028, made its first public appearance on 7 May 2026 at Alstom and CAF’s manufacturing site in Hauts-de-France.
The train will be operated jointly by RATP and SNCF on behalf of Île-de-France Mobilités as part of a wider programme to modernise the RER B network.
Designed for one of Europe’s busiest commuter rail lines, the MI20 will increase passenger capacity and improve accessibility and onboard facilities. The train will offer 35 percent more overall capacity and 22 percent more seating compared with existing rolling stock.
MI20, the future RER B train
© Île-de-France Mobilités
The train includes step-free access areas, widened gangways and additional doors intended to improve passenger flow during boarding and alighting. Interior features include air conditioning, underfloor heating, USB-C charging sockets and passenger information screens providing real-time updates. Onboard video surveillance systems with live transmission capability will also be installed.
Images of the train’s interior were released alongside the unveiling, showing a double-deck layout with redesigned circulation areas and updated seating arrangements.
MI20 interior
© Île-de-France Mobilités
The introduction of the MI20 forms part of a 5 billion EUR investment programme led by Île-de-France Mobilités for the RER B line. Approximately half of the funding has been allocated to the purchase of 146 MI20 trains.
The remaining investment will support infrastructure upgrades, including a new joint operations control centre for the RER B and RER D lines and the deployment of the NExTEO automated train control system, which is intended to improve service regularity and operational management.
The RER B connects central Paris with suburbs to the north and south of the capital, including access to both Charles de Gaulle Airport and Orly Airport. The line carries close to one million passengers each day.
The arrival of the MI20 is part of a broader rolling stock renewal programme across the Île-de-France transport network. Since 2016, more than 1,500 new or refurbished trains, metro cars and trams have entered service across the region.
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