The Rome Metro (Italian: Metropolitana di Roma) is an underground public transportation system that operates in Rome, Italy. It opened in 1955. There are currently two lines, A line (identified by the orange colour) and B line (blue). A third service, the green C line, and a new branch of the B line, are currently under construction. Plans have also been revealed for a fourth line. The current network (38 km) has an X-shape with the two currently existing lines intersecting at Termini Station, the main train station in Rome.
Rome's local transport provider, ATAC, also operates several other rail services: the Roma-Lido, the Roma-Pantano and the Roma-Nord lines. The first of these, the Rome-Lido railway line, which connects Rome to the sea at Ostia, is effectively part of the metro network, is run along similar lines and using trains similar to those in service on the A and B lines. The Roma-Pantano line, although officially designated as a railway, is a narrow gauge tram line while the Roma-Nord line is a suburban railway.