Engineering
The tunnel is just over 1.6 miles (2.6 km) long and carries two standard-gauge tracks in a single tube, which is shaped like a horseshoe approximately 7.2m (23.6 feet) wide and 6.6m (21.6 feet) high.
The tunnel was mined by hand through shale, coal and sandstone, then lined with six courses of bricks (using over 23 million bricks in all) to form the horseshoe shape. It was aligned by drilling fourteen vertical shafts to provide survey points on the hillside above: after the tunnel was completed two shafts were closed and the remaining twelve were used as blast relief shafts to vent steam from the locomotives that passed through.
When completed in 1841, it was the longest railway tunnel in the world.
Read more about this topic: Summit Tunnel
Famous quotes containing the word engineering:
“Mining today is an affair of mathematics, of finance, of the latest in engineering skill. Cautious men behind polished desks in San Francisco figure out in advance the amount of metal to a cubic yard, the number of yards washed a day, the cost of each operation. They have no need of grubstakes.”
—Merle Colby, U.S. public relief program (1935-1943)