MI20: discover the future RER B train

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A new train for the RER B and a first exit for the MI20

On 7 May 2026, the MI20, the future RER B train (which will be operated by RATP and SNCF for Île-de-France Mobilités), will make its first outing in the Hauts-de-France region on the site of its manufacturers: the Alstom and CAF consortium.

The opportunity to discover it in pictures and to make the official presentations.

18,000 of you voted to choose its design

MI20: all the details of the new RER B train

Interior of MI20 seen from the first level on one level towards the stairs that lead to the first floor and the basement
Interior of MI20 seen from the first level on one level towards the stairs that lead to the first floor and the basement

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Interior of MI20 seen from the first level on one level towards the stairs that lead to the first floor and the basement © ALSTOM SA 2026 - Samuel Dhote | MI20

  • More spacious : +35% capacity and +22% seating
  • 100% accessible with walk-in areas
  • On board: air conditioning in summer and underfloor heating in winter
  • On-board video surveillance with live transmissions
  • USB-C ports and real-time information displays to stay connected
  • Widened corridors and + entrance doors to simplify movement

RER B: investments to revolutionise passenger journeys

To ensure comfort and reliability on the RER B line, which is essential for the travel of millions of Ile-de-France residents and tourists (it is the second busiest line in Europe after the RER A!), 5 billion euros will be invested by Île-de-France Mobilités.

  1. The first half of the financing is dedicated to the purchase of 146 new trains, the MI20.
  2. The other part: the commissioning of a new command centre (common to the RER B and D) and the arrival of an automatic pilot system (NExTEO) to improve punctuality and performance on the line.

The modernisation of transport continues on the Ile-de-France network

The arrival of new trains on the RER B is part of the revolution in Ile-de-France transport, which has been carried out since 2016 by Île-de-France Mobilités.

Since then, 1,550 new or renovated trains, RER, metros and trams have joined your lines.

More comfortable and modern, they are better suited to your needs.

What's changing for your transport in 2026