It’s jacket weather outside, but miles inside the Swiss Alps it’s balmy, thanks to heat from the planet’s core. Wearing a red hard hat and carrying a backpack with an emergency oxygen tank, I’m sweating as I get a rare look at the newest wonder of the world—the 35.4-mile Gotthard Base Tunnel, the longest tunnel on earth, a $12 billion marvel that took 17 years to dig and will begin full operation on December 11.
For all their stark beauty, the Alps have always posed a heck of an obstacle to trains traveling between the North Sea and the Mediterranean. Since 1882, the old 9.3-mile Gotthard tunnel has had to suffice, but at more than 3,600 feet of elevation, it’s a slow, if scenic, traverse. Swiss citizens voted to go under the mountains in 1992, and 2,600 workers in round-the-clock shifts have done just that.
Four massive boring machines—tubular mobile factories each stretching the length of four football fields—gnawed out the twin tunnels, delving under a mile and a half of rock. Drill heads fitted with 58 seventeen-inch rock-chomping steel “roller cutters” pushed against the stone with a 26-ton force, progressing at 130 feet or so per day. When the north and south tunnels finally met in the middle, after roughly 18 miles of drilling from either direction, they were off by only a few centimeters—and ahead of schedule. Almost all of the 28 million tons of excavated rock was reportedly reused, much of it to form the tunnels’ concrete lining.
Swiss Federal Railways trains will whisk up to 15,000 passengers per day through the tunnels at 155 miles per hour, cutting the ride from Zurich to Milan from four hours to three. But the real boon will be in moving goods through Europe. The tunnel can accommodate 260 cargo trains per day—four times as many as the nearest tunnel in use—and those trains can carry much greater loads, from Swiss chocolate to Italian cars. One result will be cleaner air: 40 million tons of freight will travel through the tunnel annually, shifting cargo hauled by 650,000 trucks each year from roads onto rails. “We didn’t invent the railway,” says Daniel Achermann, a Federal Railways official, “but now we Swiss are the best at building them.”