Saturday, June 23, 2007

Alpine railroad tunnels - Switzerland

Switzerland’s government-owned, 3,100-mile (5,000-kilometer) railroad network is world renowned for its efficiency, despite the difficulties imposed by the mountainous terrain. Two of the four major rail links that pass through the small, landlocked country to connect northern Europe and Italy cross the 13,000-foot-high (4,000-meter) Swiss Alps. That access was made possible only by the remarkable engineering feats embodied in the construction, between 1872 and 1922, of the St. Gotthard, Simplon, and Lötschberg Tunnels, drilled through the rock thousands of feet underground. However, the Swiss were not the first to conquer the mountains.

The earliest European alpine railroad tunnel, the Frejus Tunnel, was drilled through Mont Cenis to connect Bardonecchia in the Italian province of Savoy (north of the Alps), through Switzerland, with Modena on the Italian peninsula. King Carlo Alberta of Sardinia championed the scheme in 1845, and his successor Victor Emmanuel II took it up in 1849. Drilling did not begin on the 8-mile (13-kilometer) double-track tunnel—over twice the length of any before attempted—until late 1857, supervised by the engineer Germain Sommeiller (1815–1871), assisted by Sebastiano Grandis and Severino Grattoni. Sommeiller patented the first industrial pneumatic drill, which greatly expedited the work. Finished in 1870, the tunnel was opened, in 1871, just two months after his death.

The following year, work began on a 100-mile (160-kilometer) railroad, the Gotthardbahn, which crossed the Lepontine Alps in south-central Switzerland to link Zurich, at the heart of the country’s northern commercial centers, with Chiasso at the Italian frontier. Before then the way across the Alps, used for 800 years, was over the 6,935-foot (2,114-meter) St. Gotthard Pass. A road was built in the 1820s. Alfred Escher the founder of Credit Suisse, was the initiator of the Gotthardbahn, and as its president, with Emil Welti he negotiated German and Italian cooperation for the project in 1869–1871. Two feeder lines meet at Arth-Goldau; from there the mountain section runs through Brunner, Fluelen, and Altdorf to Erstfeld. There it commences the steep climb to Goeshenen at the northern end of the St. Gotthard Tunnel. Designed by the Geneva engineer Louis Favre, the double-track tunnel is 9.25 miles (15 kilometers) long, passing through the mountain 5,500 feet (1,700 meters) below the surface. The southern ramp is even steeper, and at Giornico more loops take the line to Chiasso. The tunnel was drilled from both ends, and the bores joined in 1880. The railroad was opened in 1882, when the difficult approach lines were completed. Favre had accepted punishingly tight schedules for the contract. He drove his force of 4,000 immigrant laborers to cut almost 18 feet (5.4 meters) a day—over twice that achieved in the Frejus Tunnel—in horrifying working conditions: water inrushes, rock falls, dust, and (because of the great depth) temperatures up to 102°F (39°C). About 1,000 men suffered serious injury; 310 were killed.

Twenty years later, the safety record on the Simplon Tunnel, although far from perfect, was much better. From the thirteenth century, the 6,590-foot (2,009-meter) Simplon Pass near the Swiss-Italian border was a key to trade between northern and southern Europe; and in the beginning of the nineteenth century, probably for military reasons, Napoléon I ordered a road built over it. Begun around 1898, the Simplon Railroad connects the Swiss town of Brig with Iselle, Italy. Its 12.3-mile (19.8-kilometer) tunnel—in reality two tunnels—under Monte Leone was conceived as a twin-tube single-track system by the German engineer Alfred Brandt; separate galleries 55 feet (17 meters) apart were linked with cross-hatches. Until the completion of Japan’s Seikan Tunnel in 1988, the Simplon Tunnel was the world’s longest railroad tunnel. Because of its depth—up to 7,000 feet (2,140 meters) below ground—temperatures exceeding 120°F (49°C) were faced during construction.

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