of the Federal District from 2006 to 2012 and Felipe Calderón, President of Mexico from 2006 to 2012. Temporary partial closure In an unprecedented event in the history of Mexico City Metro, Line 12 had to be shut down temporarily in the stretch Tláhuac–Atlalilco due to severe faults in its infrastructure. This section is the one that corresponds to the elevated stretch of the line. The technical and structural faults of the elevated stretch caused the trains to run on the verge of derailment, due to wear on the rails that provoked slopes and damage to the tires of the trains, putting six out of the 30 trains out of service. Drivers slowed trains to as little as on some stretches for fear of derailment. The stretch was closed between 12 March 2014 and 29 November 2015, when the section going from Tezonco to Tláhuac was officially reopened by Miguel Ángel Mancera, Head of Government of the Federal District from 2012 to 2018. Previously, on October 27, 2015, the stretch Periférico Oriente–Culhuacán, resumed the service, but all trains stopped at Periférico Oriente station till the service on the whole line was reestablished. 2017 earthquake On 19 September 2017, a 7.1 magnitude earthquake hit Mexico City and other zones of Central Mexico, affecting Line 12 with electrical power shortages and the derailing of a train between the Nopalera and Zapotitlán stations. Due to this, and potential damages to the line's infrastructure, service in the Tláhuac–Culhuacán section of the line was suspended. After evaluations, it was determined that the line had visible damages in the tracks and structural faults. Therefore, the stretch from Olivos to Tláhuac was closed for repairs. Service in all the closed stations was resumed on 30 October 2017. Expansion In 2017, an expansion for Line 12 was announced. Construction started on 29 November 2017. The extension was expected to be completed by 2020, but works were delayed, thus, being projected to open by 2021. This project will extend the line from Mixcoac to Observatorio, where it will connect with Line 1 and it will have three new stations and a length of . The two new stations are Valentín Campa and Álvaro Obregón, both situated in the Álvaro Obregón borough. The totality of the extension is being constructed underground and is expected to open in December 2023. The original 1985 and 1996 plans for Line 12 considered the