What an extraordinary work of engineering this is. Two parallel 35 mile long tunnels drilled through Swiss mountains so that trains can ultimately whoosh through at up to 157 MPH. The Gotthard Base tunnel cuts an hour off the trip from Milan to Zurich. Talk about investing in infrastructure! Eric Reguly of the Globe and Mail goes way back:
The Gotthard’s opening marks the start of a logistical and trade revolution between northern and southern Europe. Ever since the time of Hannibal, the Alps and the Dolomite mountains to their east were known as a natural north-south barrier, an enormous wall made of towering peaks, glaciers and snow, and narrow, dangerous valleys.
Interestingly, the distance from Milan to Zurich is only 174 miles. The population of Zurich is under 400,000 people; Milan, about 3 million. Yet they spent US $12.3 billion to build it, to go straight through the mountains. Eric Reguly notes that it "is designed as the key component in the creation of a high-speed corridor that will whiz freight and passengers from as far north as Europe’s busiest port – Rotterdam, in the Netherlands – all the way south through Switzerland and into Italy’s northern industrial heartland."
The boring machine is a quarter of a mile long; rock is cut away with the boring head and removed via a bucket wheel on a conveyor belt. It moved 28.2 million tons of excavated rock. At its deepest point there is well over a mile of rock on top of it.
When all of the ventilation, access points and cross-passages are added in, there is over 95 miles of tunnel.
Even in Europe, projects like this take a while. The tunnel was first proposed in 1947, with the recognition that a flat straight tunnel would speed transport of people and goods. It was canned as too expensive in the 70s, approved in a referendum on 1992 and finally started in 1999. But wow, when they decide to build infrastructure, they really do it right. More at Gottardo 2016 and Designboom