ENGINEERING

摘要

In 1999, the Swiss government broke ground on the most ambitious tunnel-building project in history The dual-tube Gotthard Base Tunnel, which opened in June, follows a route that has a long history of schlepping people and goods over the Alps-it just happens to do it as deep as 1.5 miles below the icy massifs. Thanks to the precision of boring machines with 29.5-foot heads, engineers excavated 31 million tons of rock (60 percent of which was recycled into the tunnel's lining) to dig the 35-mile train passage, ushering in an era of efficient travel between points in Europe. Passengers can rocket from Zurich to Milan in three-and-a-half hours (down from just over four), and the shift of freight from roads to rails could put a real dent in air pollution. All aboard!