Precast segment production for the tunnel has reached 98%, with a total of 3,100 rings (segment sets) produced. The 5.67-kilometer-long project is adding long-term value to Sofia’s transportation infrastructure through TBM tunnel excavation with a 9.39-meter excavation diameter, the construction of three shafts, advanced engineering solutions, and high production capacity.

Building on its strong expertise in TBM and metro construction, Doğuş Construction is taking its capabilities to the next level through metro and railway projects in Romania. By extending its engineering excellence beyond borders, the company continues its growth on a regional scale.