The Transbay Tube is the part of BART which runs under San Francisco Bay in California. The tube is 3.6 miles (5.8 km) long; including approaches from the nearest stations (one of which is underground), it totals 6 miles (9 km). It has a maximum depth of 135 feet (41 m) below the surface.
The tube was constructed on land, transported to the site then submerged and fastened to the bottom (mostly by packing the sides with sand and gravel). This immersed tube technique is in contrast to bored tunneling, where rock is removed to leave a passage.
Read more about Transbay Tube: Conception and Construction, Incidents, Future
Famous quotes containing the word tube:
“One of the great natural phenomena is the way in which a tube of toothpaste suddenly empties itself when it hears that you are planning a trip, so that when you come to pack it is just a twisted shell of its former self, with not even a cubic millimeter left to be squeezed out.”
—Robert Benchley (1889–1945)