Network modernisation

RER line B: all you need to know about the summer works

This summer, we’re heading south. Works are planned on RER line B from 28 June to 20 August inclusive. Let us explain.

travaux RER B

This summer, we are continuing our upgrading works on RER line B to improve your journeys. RATP, SNCF and Île-de-France Mobilités are keeping you informed so that you can best organize your travel plans.

RER B : les travaux de l'été 2021

RER line B: 2021 summer works

Under the aegis of Île-de-France Mobilités, a master plan for improving the offer and quality of service on RER line B (SDLB) has been developed. The plan is based on concerted studies carried out by RFF (since renamed SNCF Réseau), SNCF and RATP, who were also responsible for drafting it. Approved in 2012, the plan notably provides for the addition of new trains to meet increased transport capacity goals.

The plan additionally provides for the creation of a track extension to the turning loop at Orsay station, to allow trains to turn around more easily. In this context, infrastructure work on the platforms and tracks is under way at Orsay-Ville station to create a second turning loop. Started in summer 2016, the work will be completed this summer with the commissioning of a turning loop at Orsay-Ville station to improve regularity on RER line B. This major project will result in increased train frequency.
Other works planned under the master plan include the optimization of turning facilities at Saint-Rémy-lès-Chevreuse station. In summer 2021, a new signal box and a local switching station will be installed, along with new track equipment.

In practical terms, two closures are planned in connection with all this work:

  • Between Le Guichet and Saint-Rémy-lès-Chevreuse stations:
    Service will be suspended from 10 July to 11 August inclusive. A replacement bus service will be implemented.



  • Entre Palaiseau et St Rémy-lès-Chevreuse

Le trafic sera interrompu du 12 août au 20 août inclus. Un dispositif de bus de remplacement sera mis en place.


Pont de Chartres: work has begun!

As part of the upgrade of the national rail network, RATP and SNCF Réseau have undertaken works to replace two century-old rail bridges in Massy (near Massy-Verrière station): Pont de Chartres for RER line B and Pont de Gallardon for RER line C. To find out more about the project, consult our dedicated page bu clicking here.

In practical terms, this means a closure between Les Baconnets and Massy-Palaiseau stations from 24 July to 11 August 2021.


Infrastructure upgrades

In order to run the new-generation trains ordered by Île-de-France Mobilités for 2025, the line infrastructure must be upgraded now. The work mostly involves adapting the platforms and tracks to the new trains. The project also provides improved passenger facilities at our stations, with new exits to the street and guaranteed secure accessibility for all.
Therefore, several stations will be closed this summer:

  • Fontaine-Michalon station will be closed from 28 June to 23 July inclusive. Trains will not stop at Fontaine-Michalon station. You can take the regular bus route 9 from Antony station as a replacement.



  • Luxembourg station will be closed from 1 to 31 July inclusive. Trains will not stop at Luxembourg station. You can take bus route 38 as a replacement.


  • Denfert-Rochereau station will be closed on weekends from 24 July to 22 August inclusive. Trains will not stop at Denfert-Rochereau station. You can take metro lines 4, 6 or 5 or bus route 38 as a replacement.
    Note that works will also be carried out on metro line 4: to find out more, consult our dedicatet page.


Other works on the line

Châtelet station

  • Renewal of several pieces of track equipment: the line will be closed between Gare du Nord and Denfert-Rochereau stations at midnight from 9 to 13 August inclusive.
  • Work to adapt the infrastructure for RER NG (RER line D): 4 out of 5 tracks for RER lines B and D over the summer.

To keep you best informed

Like every summer, all RATP and SNCF teams will be in action to guide and support you during the closure of RER line B. Many educational and informative tools will soon be available to allow you to best prepare for these periods of service suspension on the line.

Until then, you can consult this dedicated page, which will be regularly updated, as well as the 
RER B blog and the  Twitter line account .