The A line connects the north-west of the city with the south-east. It currently has 27 stations with terminals at Battistini and Anagnina. Its distinguished by the colour orange.
Approval was given for the construction of the Rome's second metro line in 1959. Subsequently called the A line it would run roughly perpendicularly to the existing metro line, now called the B line.
Works on the A line began in 1964 in the Tuscolana area but were subject to a series of delays caused by poor organisation. Above all, the originally planned method of construction of cut and cover posed serious problems for road traffic in south-east Rome. Work on the metro was suspended and began again 5 years later, using bored tunnels which partially resolved the traffic problems but caused numerous claims for compensation arising for vibrations caused by the boring machine. Work was also frequently interrupted by archaeological finds made during the excavations, particularly near Piazza della Repubblica.
The A line finally entered into service in February 1980. In the late 1990s it was extended from Ottaviano in Prati to Battistini to the west.