RER B works: dates, times and alternatives from October to December 2026 Last updated: October 1, 2026
As part of modernization works, the RER B line will undergo works in 2026 on several dates and sections. These closures have a direct impact on your travel: find the schedule and our advice in this article.
Key dates
As part of the RER line works 
, service disruptions are scheduled on these routes:
🚫 All day:
- Aulnay-sous-Bois <> Mitry-Claye
🚫 In the evening from 10:45 p.m.:
- Aéroport Charles de Gaulle 2-TGV / Mitry-Claye <> Châtelet – Les Halles
- Aulnay-sous-Bois <> Aéroport Charles de Gaulle 2-TGV
Alternative routes
Click on the diagrams to see all the alternatives according to your departure and arrival point🚫 Aéroport Charles de Gaulle 2-TGV / Mitry-Claye ↔ Châtelet – Les Halles
Replacement buses will be provided and the regular bus line will be reinforced. You can take the recommended alternative routes shown in the diagram below, allowing for a longer journey time.
🚫 Aulnay-sous-Bois <> Mitry-Claye
A replacement shuttle service (the B3 shuttle) will operate during this period.
🚫 Aulnay-sous-Bois <> Aéroport Charles de Gaulle 2-TGV
The replacement bus B4 will operate during this period.
Adapt your journeys with the Bonjour RATP app
🔎 Find the best route
Start a route search: the results anticipate disruptions to help you avoid construction areas. Then customize according to your needs: schedules, transport modes, lines or stations to avoid…
🚦 Check live traffic information
Access real-time traffic status via the app's Traffic tab. You can enable personalized alerts to be notified when your lines are affected.
📹 Demo: follow traffic updates with the app
The Bonjour RATP app, your ally for anticipating disruptions and
finding the best routes during construction work
