The Brenner base tunnel is about 57 km long and constitutes the middle section of the high-capacity railway between Munich and Verona. It consists of two single-track rail tunnels or tubes. The distance between the twin tubes is 70 m for most of the section, decreasing to approximately 40 m in the vicinity of the portals.
Bypasses constructed every 333 m link the two tubes. The system configuration is completed by a drainage tunnel about 10 m below and between the twin tubes. During the construction phase, the drainage tunnel was used for logistics. The base tunnel is mainly straight, except for the southern approach to the Fortezza portal and station.
The gradient is constant both in Italy and in Austria; the lowest altitudes are at the two portals, whereas the tunnel apex is in correspondence with the border between Italy and Austria. The tunnel depth is significant, with maximum coverage of about 1,600 m, and average coverage of nearly 900 m.