TBM deployed on the Riyadh Metro Line 3 arrives at Downtown station November 18, 2016 | Middle East & Africa Company News Italy-based Salini Impregilo has announced that a tunnel boring machine (TBM) has excavated a 4.34-km tunnel of Riyadh Metro Line 3 (Orange Line) and reached Downtown station. The Impregilo-led Arriya... This content is available to only subscribers. Username or E-mail Password Remember Me Forgot Password