Île-de-France Mobilités has confirmed that heavy track and signalling upgrades on the RER B – Paris’s primary rail artery to Charles-de-Gaulle (CDG) and Mitry-Claye – will cause nightly and, in parts of the line, all-day service suspensions through mid-August. The real-time bulletin posted on 28 July 2026 notes that until 16 August from 22:45 each evening, no trains run between Gare du Nord and CDG Terminal 2 TGV / Mitry-Claye, with buses replacing the missing segment. A separate blockade between Bourg-la-Reine and Gare du Nord remains in effect around the clock until 6 August. The RER B normally carries about 90 000 air passengers a day and is the preferred option for corporate travellers heading to meetings in central Paris. The closures coincide with the peak tourist season and a busy trade-fair calendar at Parc des Expositions Villepinte, raising concerns about longer door-to-door times and missed early-morning flights. Airport operator ADP is advising passengers to allow at least one extra hour and consider alternative routes such as the CDG Express coaches, taxi-VTC services or car-sharing. For companies running tight day-trip itineraries, the bus shuttles – which add an average 35-45 minutes depending on traffic – may negate the advantage of flying via Paris. Travel managers are therefore rerouting some staff through Orly, moving meetings online, or booking hotels near CDG to avoid late-night returns. Airlines have issued precautionary check-in reminders and some are waiving rebooking fees for passengers who miss connections because of surface-transport delays. The works form part of a €2.2 billion ‘Cœur de Ligne’ modernisation that will eventually boost frequency and reliability ahead of the Paris 2028 Olympics. SNCF Réseau says the current phase involves replacing 45 switches, renewing overhead lines and installing a digital signalling system that will allow 32 trains an hour through the central tunnel. While the upgrades promise long-term benefits, stakeholder groups such as the Paris Île-de-France Chamber of Commerce are calling for better real-time information in English and clearer signage at Gare du Nord to guide non-French-speakers to the correct replacement buses. Travellers can sign up for push notifications via the RATP app or follow the @RERB account on X (formerly Twitter). Those with tight morning departures from CDG during the works window may wish to stay overnight at an airport hotel or pre-book guaranteed-fare taxis to avoid traffic-related fare surges.
Source: RATP – Info Trafic RER B
