Thursday 10 March 2011

Alps Railway Tunnel


When the Welsh chronicler Adam of Usk traveled over Switzerland's wild and remote Gotthard Pass by oxcart on his way to Rome in 1402, he was so terrified that he asked his guides to blindfold him so he wouldn't have to look.
He wasn't the first alpine traveler to wish there were another way. For thousands of years, the Alps have been the great barrier to travel and trade on the Continent. To cross them meant a drawn-out, often perilous trip, or at the very least a tough uphill slog.
Not for much longer. For the past nine years, an army of tunnelers has toiled deep in the hard granitic core of the mighty mountain range known as the Gotthard Massif, constructing the world's longest and deepest railway tunnel.
Last October miners burrowing north from the Italian-speaking canton of Ticino met their counterparts who'd been boring south from German-speaking Sedrun to conclude the digging phase of one bore of the double-barreled tunnel—a handshake moment televised live on Swiss TV and broadcast across Europe. In April, the final breakthrough is expected in the second tube.
At 57 kilometers long (35 miles), the Gotthard Base Tunnel will handily outstrip the 50-kilometer (31-mile) Channel Tunnel between England and France and the present record-holder, Japan's 54-kilometer-long (33.6-mile-long) Seikan Tunnel. It will stand alone on the engineering front as well. Where its nearest rivals both pass beneath relatively shallow bodies of water, the Gotthard cuts through the complex basement rocks of a giant, heavily folded mountain range. No one has ever tunneled so deep into a mountain, or to such transforming effect.
When it opens, in 2017, it will render Switzerland, for railroading purposes, as flat as Holland. High-speed passenger trains southbound from Zurich will race along a nearly level course all the way to Milan, booming through the Swiss countryside as fast as 250 kmh (155 mph), flashing in one side of the mountains and popping out the other a few minutes later. It will be as though the Alps didn't exist. Travel time between the cities will drop from nearly four hours to just over two and a half—quicker and more direct than if you flew.
Beating out the airlines isn't why the Swiss are spending $10 billion on the tunnel: They're doing it to shift freight, and to curb the spiraling number of trucks clogging their highways and rumbling through their fragile alpine backyard.
Truck traffic has grown exponentially in the sleek new borderless Europe, especially in the Alps, which straddles the fast-growing economic regions of southern Germany and Italy's industrial north. Quiet, neutral, traditionally aloof Switzerland has become a main trucking crossroads. More than a million trucks a year travel over its passes on winding mountain highways and through alpine road tunnels primarily designed for holiday traffic in the 1960s.
The solution, the Swiss decided, was to boost the capacity of the railways to handle freight. And the best way to do that would be to write the mountains and their famous passes out of the equation: Run a set of tracks straight through the bottom of the mountains and out the other side. With no gradients to climb, trains could haul loads twice as heavy and travel twice as fast as those using the old alpine railways. The Gotthard tunnel alone will be able to handle 40 million tons of cargo a year.
The tunnel begins its journey under the 2,108-meter (6,196-foot) pass in the quiet hamlet of Erstfeld, plunging into a hillside through twin concrete portals. It doesn't come out again until Bodio, more than 57 kilometers (35 miles) away, having crossed one of the Continent's great divides. They speak German when you go into the tunnel; Italian when you come out. A rainy day in the quiet hamlet of Erstfeld is likely to be a sunny one in Bodio, and vice versa.
The tunnel avoids the highest (and weightiest) peaks. Its sinuous path seeks out the most favorable geology and skirts potential groundwater complications with lakes that dot the surface some 2 kilometers (1.2 miles) overhead. Five years and $115 million Swiss francs were spent on fieldwork, drilling, soil samples, and a remote sensing survey to map the massif's nooks and crannies to an accuracy of about ten meters.
Nothing about the Gotthard project is small. In the course of building the tunnel, workers will excavate 25 million tons of rock, enough to fill a freight train stretching from Zurich to New York or, if you're so inclined, to build five life-size replicas of the Great Pyramid. Some of the dross will be dumped in Lake Lucerne to create an offshore nesting area for birds. The better quality stuff will be ground up for concrete to line the passage. In all, some 152 kilometers (94 miles) of tunnel will be dug and lined—two main bores, at 57 kilometers (35 miles) each, plus kilometers of access shafts, emergency escape passages, ventilation ducts, and crossover points, so trains can shift channels when tracks need repair or maintenance.

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