The first section is 12.5km long and runs from Parco Centocelle east to Monte Compatri-Pantano. There are 15 stations, five of which are new and the remaining 10 have been rebuilt as they are on the old Roma Laziali - Giardinetti surface line which has been upgraded to metro standards. The line has 4.3 km of underground track constructed in parallel tubes up to 30m in depth.

The six-car driverless trains, which can carry up 1200 passengers, have been supplied by AnsaldoBreda, while Ansaldo STS was responsible for the signalling. The civil works were executed by a consortium comprising Astaldi, Vianini, Consorzio Cooperative Costruzioni, and Cooperativa muratori e braccianti di Carpi.

Line C currently operates until 18.30 with trains running at 12 minute intervals. However, it is planned to run a more intensive service.

The line is being extended towards the city centre, and is expected to open as far as Lodi on December 31, which will add six stations. A one-station extension to San Giovanni is scheduled to open on December 31 2015 which will provide an interchange with Line A. It is hoped to extend Line C to Fori Imperiali-Colosseo by September 2020 which will enable passengers to interchange with Line B.