Opened in June 2012, the B1 Metro line connects piazza Bologna to viale Jonio. Involving about 1,100 engineers, technicians and workers engaged in the early stages of monitoring, planning and construction, and an investment by the Ministry of Transport and the Municipality of Rome, the B1 stretch connects the northeastern neighborhoods of Rome - Nomentano, Trieste, Montesacro, the African district - with Eur, Magliana, Pietralata and Tiburtina neighborhoods.
With the opening of the Bologna/Jonio stretch, the trains of metro line B follow two paths: from Laurentina to Jonio and vice versa and from Laurentina to Rebibbia and vice versa. The stretch shared by both routes is Laurentina-Bologna: from here some of the trains continue (as usual) on to Tiburtina station and Rebibbia and some others take the new line stopping at the stations of S. Agnese/Annibaliano, Libia, Conca d'Oro and on to the terminus of Jonio. Trains between Laurentina and Jonio are therefore direct lines, requiring passengers to make no change at the Bologna stop. The destination of the train is communicated by the display and speakers at the platform, while on board the next stop and the final destination are announced.
The Metro B1 line has a transport capacity of 24,000 people per hour in each direction. The stations are developed in depth, on several levels connected by elevators and escalators (in addition to the normal non-mechanized stairways). The feature of each structure is the presence of an underground square, which also serves to alleviate any feeling of discomfort caused by the descent in depth to access the trains. At stops of S. Agnese/Annibaliano and Libia, the quays of the trains are superimposed; the deepest depth is reached by Libia station, with the 36 mt from the road level to one of the two platforms.
Le nuove stazioni e tracciato della metro B1
The structure is laid out on 4 levels, connected by escalators and elevators that lead to level -1 (where the turnstiles are found) and -4 (where the platforms of the stop are found); there are special systems and paths for users with reduced mobility, or who are sight- or hearing-impaired. In the Conca d'Oro-Jonio stretch (1.5 km) the trains run through a tunnel with a double track, 10 meters in diameter with the platforms placed at the same level about 28 meters below street level.
Conca d'Oro station
Three levels and a large underground square that is meant to be a meeting point and hub for the flow of travelers: these are the characteristics of the Conca d'Oro station on the new B1 stretch. The first level is eight meters above street level: from here one descends to the lobby of the station, to then reach the train platforms, located on the same level, 20 meters below street level. The atrium and platforms are connected to the surface by escalators and lifts.
S. Agnese/Annibaliano station
S. Agnese/Annibaliano Station is the first stop coming from piazza Bologna and is named after the nearby monumental complex of St. Agnes outside the Walls. The station is built on three levels. The first, at a depth of ten meters, is a space designed as an underground square, a common element in the three new stations. The station atrium is found on the same floor. Elevators and stairs, as well as escalators, connect the atrium with the train platforms, superimposed on two different levels, at 19 and 30 meters from street level, respectively.
The use of natural light as an architectural element is the peculiar feature of Libia station, along the new B1 metro route. The technique of the day-lighting shaft allows for the illumination of the block of stairs all the way down to the deepest level. Also in Libia station, a small underground square, six meters below street level, enters the foyer and from here descends to the platforms, set on two different levels. The atrium and platforms are connected to the street level by escalators and lifts.
The route of the B1 metro line
The tunnels of the B1 metro line were constructed at a depth of 25-30 meters below street level. The need to create tunnels without harming the pre-existing elements, such as the man-made fork for Bologna station or the foundations of the buildings and bridge of the Valli area, have necessitated the construction of mono-rail tunnels, of about 7 meters in diameter. The route runs entirely underground along viale XXI Aprile, piazza Annibaliano, viale Eritrea, viale Libia, via delle Valli, to Piazza Conca d'Oro and viale Jonio.