The circular line will be the first Metro line to have this automatic element, as it is the most heavily used line in the entire underground network, with more than 90 million journeys recorded in the first six months of the year.

According to the Community of Madrid, these automatic doors will be installed on the line's 70 platforms, totalling 6.4 kilometres, and will separate the passenger waiting area from the train circulation area, thus guaranteeing "safe and orderly" entry to the train.