Line C:

The project for Line C of the Rome Metro, the third line envisaged by the Town General Plan, aims to directly connect currently distant areas and neighbourhoods by crossing the city from northwest to southeast. Once completed, Line C will increase the development of the existing metro network by more than 50%.

The "Fundamental Route" of Line C, extended over a length of 25.5 km and equipped with 29 stations, begins on the surface in the territory of the Municipality of Monte Compatri and follows the route of the existing Termini-Pantano railway. Subsequently, it descends underground just before the Grande Raccordo Anulare, crossing the historic centre to the Mazzini neighbourhood. Along its route, Line C intersects Line A (San Giovanni and Ottaviano), Line B (Colosseo), the future Line D (Venezia) creating an effective "network effect".

The route, now fully funded, is divided into sections whose construction began with those further east: T2 under design, T3 under construction, T4-T5, T6 and T7 with the Granite Depot/Workshop, completed and operational. The subdivision of the Fundamental Route into sections derives from the different progress state of the designs at the time of the inclusion of the work in the Objective Law (2003), with the consequent approval and financing procedures. 

The route of the T3 Section, which falls entirely within a historical-monumental context unique in the world, develops for a total length of about 3 km from Piazzale Appio to Via dei Fori Imperiali. The project includes 2 stations, Porta Metronia and Colosseo/Fori Imperiali, two multifunctional shafts, respectively in the gardens of Via Sannio and Piazza Celimontana, and 2 line tunnels of 5.8 m in diameter each, almost entirely made with TBM.

The part of Section T3, which includes the line tunnels from San Giovanni to Via Sannio (built using the traditional method), the multifunctional shaft in Via Sannio, and the section of the line tunnels to Porta Metronia Station (built using mechanised excavation through TBM), has already been delivered to the Administration with minutes of advance delivery art. 200 Presidential Decree 554/99 dated 18/06/2021, and was then subject to the authorisation for operation by Lazio Region Decree No. G10991 dated 11/08/2022. The early completion of this part made it available to the Merchant a railway communication (at the multifunctional shaft) through which the reversal of the trains upstream of the current provisional terminus of San Giovanni can take place, thus allowing the use of both station platforms.

At the moment, the construction of the remaining part of the Section is being completed, with the two stations and the Celimontana shaft: the civil works are substantially completed and progress is being made with the architectural finishes and the plant part, both station and line. As of 31/12/2023 (SAL 63 as of 31/08/2023) there is a total accounted amount of € 583,118,525.58 plus VAT, which represents about 86% of the total contractual amount (€ 676,601,467.92 plus VAT). The net amount accounted for the works only is € 492,322,455.73 plus VAT, corresponding to about 89% of the total reference amount from the updated Economic Framework, which amounts to € 553,539,226.11 plus VAT.

In particular, the value of the works of the stations with respect to the total works (about 550 million euros) amounts to: about 90 million for the Porta Metronia station, 120 for the Colosseo/Fori Imperiali station, 200 for the line tunnels, 80 for the plants, and 60 for the remaining items (shafts, special works and more).

Colosseo/Fori Imperiali Station:

The Colosseo/Fori Imperiali station of Line C of the Rome metro extends below Via dei Fori Imperiali, positioning itself between the Colosseum and the area in front of the Basilica of Maxentius. This station will be equipped with two distinct entrances: one on the Clivo di Acilio side and the other on the Clivo di Venere Felice side, thus allowing an interchange with Line B.

The Colosseo/Fori Imperiali station will provide access to the platforms of the Colosseo station of Line B via a direct underground link, part of which will overpass the tunnel of the Colosseo station of Line B and enter the Colosseum Shaft (Pozzo Colosseo). This new structure, made with the top-down method between reinforced concrete diaphragms, extends for about 240 metres, with a width ranging from 30 to 60 metres and a depth of 32 metres from the street level, divided into five levels.

The area where the station is located is of considerable historical importance, being next to the Flavian Amphitheatre, the Basilica of Maxentius, the Temple of Venus and Rome, and the areas of Villa Rivaldi. The construction of the station involved the ancient hill of Velia, largely removed for the construction of the Via dei Fori Imperiali in 1932, bringing to light several archaeological structures.

Although these excavations have compromised much of the archaeological pre-existence underground, archaeological investigations and excavations of the station and the Colosseum Shaft (Pozzo Colosseo) have brought to light, among other things, "archaic" shafts for the collection of groundwater, parts of buildings of the late Republican and early imperial ages, remains of a large circular structure (probably a fountain) and a rectangular basin with marble coating attributable to the Flavian era. In addition, on the Clivo di Acilio and Villa Rivaldi side, the stratigraphy and structures saved by the cutting of the Velia and preserved behind the containing wall of Antonio Muñoz, pertinent to the imperial age residential buildings of the southeastern slope of the hill, were exhibited. Below the filling levels of the early modern age, the remains of an articulated complex of structures dating from the early imperial age to late antiquity emerged.

The project of the station includes two variants during construction due to archaeological findings: one concerning the exhibition arrangement and the other the Clivo Acilio side. The first consists in the relocation of the archaeological findings discovered during the excavations inside the station, with display cases and dedicated routes, while the second involves the relocation of the ancient walls found along the Clivo di Acilio, under the responsibility of the Archaeological Park of the Colosseum.

In summary, the museum spaces of the station will be organised into five areas: transformations of the area of the Imperial Forums, shafts from the archaic era, the ancient landscape of the Velia, ritual shafts, and a "Forum" of the station.