In 2015 the city council approved the expansion to double-track the part of line 18 between Brühl-Mitte and Brühl-Badorf. By December 2018, the new tracks had been built, but because a new railway control center and required inspections had delays, the new track could be opened in April 2019. Additional construction such as the upgrade of platforms along the track was finished by mid 2020.
