page_title: Tunnel
section_title: In history
hierarchical_section_title: Tunnel / Examples / In history
caption_attribution_description: English: Composited digital illustration depicting the West portal of the CPRR's "Summit Tunnel" (Tunnel #6) which was in continuous use by the CPRR, SPRR, and UPRR from 1868 to 1993 at Donner Pass (Norden, California) on Track #1 of the original "Sierra Grade" of the Central Pacific Railroad. (The tracks removed in 1993 have been digitally restored in this illustration.)
context_page_description: A tunnel is an underground passageway, dug through the surrounding soil/earth/rock and enclosed except for entrance and exit, commonly at each end. A pipeline is not a tunnel, though some recent tunnels have used immersed tube construction techniques rather than traditional tunnel boring methods.
  A tunnel may be for foot or vehicular road traffic, for rail traffic, or for a canal. The central portions of a rapid transit network are usually in the tunnel. Some tunnels are aqueducts to supply water for consumption or for hydroelectric stations or are sewers. Utility tunnels are used for routing steam, chilled water, electrical power or telecommunication cables, as well as connecting buildings for convenient passage of people and equipment.
  Secret tunnels are built for military purposes, or by civilians for smuggling of weapons, contraband, or people. Special tunnels, such as wildlife crossings, are built to allow wildlife to cross human-made barriers safely. Tunnels can be connected together in tunnel networks.
context_section_description: The history of ancient tunnels and tunneling in the world is reviewed in various sources which include many examples of these structures that were built for different purposes. Some well known ancient and modern tunnels are briefly introduced below:
  The qanat or kareez of Persia are water management systems used to provide a reliable supply of water to human settlements or for irrigation in hot, arid and semi-arid climates. The deepest known qanat is in the Iranian city of Gonabad, which after 2700 years, still provides drinking and agricultural water to nearly 40,000 people. Its main well depth is more than 360 m (1,180 ft), and its length is 45 km (28 mi).
  The Siloam Tunnel was built before 701 BCE for a reliable supply of water, to withstand siege attacks.
  The Eupalinian aqueduct on the island of Samos (North Aegean, Greece) was built in 520 BCE by the ancient Greek engineer Eupalinos of Megara under a contract with the local community. Eupalinos organised the work so that the tunnel was begun from both sides of Mount Kastro. The two teams advanced simultaneously and met in the middle with excellent accuracy, something that was extremely difficult in that time. The aqueduct was of utmost defensive importance, since it ran underground, and it was not easily found by an enemy who could otherwise cut off the water supply to Pythagoreion, the ancient capital of Samos. The tunnel's existence was recorded by Herodotus (as was the mole and harbour, and the third wonder of the island, the great temple to Hera, thought by many to be the largest in the Greek world). The precise location of the tunnel was only re-established in the 19th century by German archaeologists. The tunnel proper is 1,030 m long (3,380 ft) and visitors can still enter it.
  One of the first known drainage and sewage networks in form of tunnels was constructed at Persepolis in Iran at the same time as the construction of its foundation in 518 BCE. In most places the network was dug in the sound rock of the mountain and then covered by large pieces of rock and stone followed by earth and piles of rubble to level the ground. During investigations and surveys, long sections of similar rock tunnels extending beneath the palace area were traced by Herzfeld and later by Schmidt and their archeological teams.
  The Via Flaminia, an important Roman road, penetrated the Furlo pass in the Apennines through a tunnel which emperor Vespasian had ordered built in 76–77 CE. A modern road, the SS 3 Flaminia, still uses this tunnel, which had a precursor dating back to the 3rd century BCE; remnants of this earlier tunnel (one of the first road tunnels) are also still visible.
  The world's oldest tunnel traversing under a water body is claimed to be the Terelek kaya tüneli under Kızıl River, a little south of the towns of Boyabat and Durağan in Turkey, just downstream from where Kizil River joins its tributary Gökırmak. The tunnel is presently under a narrow part of a lake formed by a dam some kilometers further downstream. Estimated to have been built more than 2000 years ago, possibly by the same civilization that also built the royal tombs in a rock face nearby, it is assumed to have had a defensive purpose.
  Sapperton Canal Tunnel on the Thames and Severn Canal in England, dug through hills, which opened in 1789, was 3.5 km (2.2 mi) long and allowed boat transport of coal and other goods. Above it the Sapperton Long Tunnel was constructed which carries the "Golden Valley" railway line between Swindon and Gloucester.
  The 1791 Dudley canal tunnel is on the Dudley Canal, in Dudley, England. The tunnel is 1.83 miles (2.9 km) long. Closed in 1962 the tunnel was reopened in 1973. The series of tunnels was extended in 1984 and 1989.
  Fritchley Tunnel, constructed in 1793 in Derbyshire by the Butterley Company to transport limestone to its ironworks factory. The Butterley company engineered and built its own railway a victim of the depression the company closed after 219 years in 2009. The tunnel is the world's oldest railway tunnel traversed by rail wagons using gravity and horse ha
caption: The 1,659-foot (506 m) Donner Pass  Summit Tunnel (#6) was in service from 1868 to 1993.
exif: {"Image Orientation": "Horizontal (normal)", "Image XResolution": "72", "Image YResolution": "72", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "Adobe Photoshop CS4 Macintosh", "Image DateTime": "2009:06:07 16:57:28", "Image Artist": "CPRR.org", "Image Copyright": "Copyright \u00a92003 CPRR.org - By using this image, I acknowledge that I have read and agree to the CPRR.org User Agreement.", "Image ExifOffset": "320", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "458", "Thumbnail JPEGInterchangeFormatLength": "11958", "EXIF ColorSpace": "Uncalibrated", "EXIF ExifImageWidth": "700", "EXIF ExifImageLength": "864"}