Expansion of the Rome metro - an urgently required measure in view of endless traffic congestion on city bound and out-bound roads. And a challenging measure at the same time: the archaeological treasuries in the underground must not suffer and life above ground must continue without disturbance. Therefore, plans for the new sections of the B1 and C Lines envisaged greater depths of the new routes.
The decision was made in favor of EPB Shields "Made in Schwanau" - seven machines in total. They offer a high degree of safety when it comes to avoiding settlement and heave during tunnelling in rather soft ground conditions under inner-city housing. For the northern branch of Line B, the future Line B1, two identical Earth Pressure Balance Shields (S-387 and S-388) were employed. The lines to be driven run from the Conca D´Oro station in southern direction up to the connection with Line B. On September 20, 2010 the S-387 reached the target shaft - the future Bologna station - after a total of 3,000 meters of tunnelling and best weekly performances of up to 161 meters. On November 15, 2011 the sister machine S-388 succeeded as well. The largest machine of the Roman septet, the S-544 (Ø 9,766mm), celebrated breakthrough on August 28, 2012.
Line C is devided in seven sections in total which are driven by four identical Herrenknecht Earth Pressure Balance Shields. Up to 180 meters per week were driven by the machines S-497 and S-480 until their breakthrough in April and June 2010. Still "on the job" are the S-409 and S-410 with best performaces of up to 500 meters per month.