What exactly does the RER A summer construction work entail?

The RER A track replacement project consists of replacing all of the tracks, ballast and train switching systems. Through 2021, a total of 24 kilometres of ballasted track, including 27 switching systems, must be entirely replaced between Nanterre-Préfecture and Vincennes. This complex operation will require traffic to be completely halted, 24 hours a day, 7 days a week for 4 weeks each summer through 2018, and then at night and on weekends for 7 to 9 weeks each summer between 2019 and 2021.

For more information on how tracks are replaced, click here.
For more information on why the tracks need to be replaced, click here.