Progress under the Alps. On Tuesday, the digging of a major section of the Gotthard Base Tunnel  was completed as the tunnel drilling machine Gabi broke through the final bits of stone deep inside the mountain range. Once completed in 2017, the €13.5 billion tunnel ($18.75 billion), 57 kilometer (35.4 mile) long tunnel (with a total of 153.5 kilometers of tunnels and shafts), will be the longest in the world. The digging is now 87 percent complete, with the final breakthrough planned for the beginning of 2011. The rail tunnel will reduce the 3.5 hour journey from Zürich to Milan by one hour and relieve traffic on other trans-Alpine routes.