Rome Metro (Metropolitana di Roma) is the oldest Metro system in Italy, dating from 1955. It is made up of three lines - A (depicted orange on maps), B (blue) and C (green). In total there are around 60km of track, serving over 70 stations.
Line B opened first, but only gained that designation when the current line A opened in 1980. Lines A and B conveniently intersect at Termini - Rome’s principal mainline train station. Line A is roughly oriented north east/south west, with line B running from the north east to the south of the city.
Line C is being opened in stages from 2014 onwards, its construction being delayed by the careful archaeology needed at surface excavations (principally stations). Line C currently heads out to the east and has an interchange at San Giovanni with line A. Further intercahnges are planned as stations further west on the line are opened in due course.
The system operates on standard gauge with an overhead power supply. Some of the trains on Line B in particular are heavily graffitied, reminiscent of New York. Line A has more modern air-conditioned stock. Line C has driverless trains, manufactured by AnsaladoBreda but now owned by Hitachi. The whole network is run by ATAC (Azienda Tramvie e Autobus del Comune di Roma).
San Giovanni station is now a so-called archeostation, as discoveries made during the construction of line C form an exhibition within the station itself. The platforms are around 20 metres below the surface and 21 separate periods were identified in the strata above. These date from contemporary finds back to the prehistoric era. Explanatory panels describe the finds, some of which are also on display.