The system is owned and operated by Azienda Tranvie e Autobus del Comune di Roma (ATAC SpA).

[2] The key node of the tram network in Rome is Porta Maggiore, where four out of six lines meet (3, 5, 14 and 19), as well as the Rome-Giardinetti railway.

This is about 1 km east of Roma Termini railway station, and not connected to the metro network.

The remainder of the line from the Roma Trastevere railway station to Piazzale Ostiense continued until 2016 to be served by a substitute bus service, the 3B, pending the completion of infrastructural works.

It connects with line A at Termini metro station, Piazza Vittorio Emanuele II and Manzoni.

Rome had horse buses after 1845, when pope Gregory XVI authorized a line from Piazza Venezia to the Basilica di San Paolo fuori le mura to transport pilgrims.

Horse trams arrived in 1877, connecting Piazzale Flaminio with the Ponte Milvio, the current line 2.

In 1895, electric trams arrived, connecting Termini station to Piazza San Silvestro.

After a few years of competition with the incumbent company SRTO, in 1929, government-controlled company ATAG (Azienda Tranvie Autobus del Governo di Roma) took over the whole network, and by the end of that year, the network had reached its largest extent: no fewer than 59 lines along 140 km of track.

After the Second World War, the operating company changed its name to ATAC (Azienda Tranvie ed Autobus del Comune di Roma), but the network kept shrinking.

The prototype, delivered in 1942 and numbered 7001, operated briefly and was destroyed in the bombing of Rome on 19 July 1943.

Trams feature in some of them: The tramway line to Cinecittà is credited to have had a crucial role in the neorealist film-making, as directors drew ideas for subjects while travelling with people from working classes.