The new infrastructure consists of a few mixed steel/concrete road viaducts, necessary mainly to cross the River Adda and the Tirano junction slip roads. It also consists of 3 natural tunnels of between 1500 and 2000 m in length, as well as an artificial tunnel about 1000 m long.
Two of the three natural tunnels (Il Dosso, 2044 m in overall length, passing through metamorphic rock formations mainly consisting of mica schists and gneiss, and Cologna, 1998 m in overall length, passing through alluvial cone deposits mainly consisting of lime-sandy gravel) are on the artery which joins the Tirano junction with the Lovero junction, while the third (Ramaione Tunnel, 1560 m in overall length, passing through metamorphic rock formations consisting mainly of mica schists) will become the future branch which connects with the national border in Val Poschiavina.
Special attention was paid to the hydrogeological issues concerning a section of the Adda River and the affluent Poschiavino, characterized by a delicate hydrogeological structure. Therefore, the new works have been designed so as not to modify the watercourse system of the territory, in particular without altering the functions of the overflow and runoff areas and allowing flood runoff in the proper areas.