Webuild Group contributed to the construction of the Bucharest Subway, through the construction of sections of Line 4 and Line 5. 

For Line 4, referred to as "Magistralia," the work carried out by the Webuild Group, in joint venture, included the construction of the extension of Line 4, along the section running from Bazilescu to Straulesti, which includes just under 1 km of twin-tube tunnel, with 2 stations and a depot with intermodal terminal all underground. 

The work resulted in the excavation of two tunnels using TBMs, large mechanical cutters that provide progressive advancement underground in a shorter time than traditional excavation techniques. In addition to structural works, facilities were also built.