RER A Summer work

FAQ RER A Summer Work

Answers to frequently asked questions about RER A Summer work can be found in this section.


What is the summer work on RER line A exactly?

The RER line A track renewal work consists in replacing all tracks, ballast and train switching systems. By 2021, there are a total of 24 km of track and ballast to be renewed and 27 switching systems replaced between Nanterre-Préfecture and Vincennes. A complex operation that requires total interruption of traffic 24 hours a day every summer for four weeks until 2018 and then for seven to nine weeks at night and weekends from 2019 to 2021.

Why can’t all the work take place at night and/or the weekend?

When track ballast is renewed, the commercial speed must be reduced to 30 km/h during a track stabilisation period.

The impact of this speed limit on train frequency is not the same on the central section, where all the trains of the line circulate, as it is on the less-busy branches.

In fact, a speed limit of 30 km/h on the central section reduces the transport offer by one-third at rush hour.

On a line that carries 308 million passengers a year and with constantly increasing traffic, a reduction of this size would have been unacceptable during the 10 to 12 years of night work that this work would have required.
In order to meet the goal of renewal by 2021, it was therefore essential to concentrate the work over long periods of interruption in the summer.

Why is the work done in the summer?

The work is done in the summer because it is the period of the year with the lowest traffic. The interruption of traffic will be less disruptive for passengers and will allow the work to be carried out more quickly. This summer closure will also be the opportunity to carry out other work that would have required service cuts and suspensions at other times.

Why does the work take so long?

By 2021, there are a total of 24km of track to be renewed and 27 switching systems replaced on the central section of RER line A, between Nanterre-Préfecture and Vincennes. To be able to carry out this work while limiting passenger inconvenience as much as possible, RATP rejected the solution of night work because it would have spread out for too many years and would have required a slow-down in traffic incompatible with the need to transport more than a million passengers every day. The solution chosen by RATP was to phase the work, with complete closure of the stations concerned each summer, as follows:

- 24h a day for 4 weeks until 2018

- nights and weekends from 2019 to 2021

What will this mean as from 2019?

Thanks to the four consecutive years of total traffic interruption from 2015 to 2018, RATP has been able to achieve its objectives so that, from 2019, it will be possible to programme a partial interruption of traffic since the work will take place at night and weekends. From 2019 until 2021, therefore, partial closure to traffic will take place each summer for seven to nine weeks.

Last year you already suspended traffic between La Défense and Nation for track renewal. Why are you interrupting the line between La Défense and Nation again this year?

On the central section, as all trains run on two tracks and in tunnels, it is impossible to carry out work without interrupting the traffic. In 2016, 2017 and 2018, phased work was carried out between La Défense and Gare de Lyon, but the interruption to traffic must be extended between La Défense and Nation to allow for train reversal, since train reversal manoeuvres are not possible at either Châtelet-les-Halles or Gare de Lyon. By 2021, 24km of track will be renewed and 27 switching systems replaced between Nanterre-Préfecture and Vincennes.

What improvements will passengers see from this work?

The main goal of the track and ballast renewal work on RER line A is to cope with the steady increase in traffic on the busiest line in Europe (+20% in 10 years, 308 million passengers a year). By renewing its tracks to receive the new double-decker trains (MI09) deployed since 2017, RER line A can increase its capacity by 30% and therefore improve passenger comfort. Moreover, by guaranteeing optimum safety, reliability and availability of its infrastructure thanks to track renewal, RER line A can improve its performance.


Closure/ Disruptions


Partnership/Alternative offer