Daylighting a tunnel

Tunnel

A tunnel is an underground passageway, completely enclosed except for openings for egress, commonly at each end.A tunnel may be for foot or vehicular road traffic, for rail traffic, or for a canal. Some tunnels are aqueducts to supply water for consumption or for hydroelectric stations or are sewers...

 is to remove its "roof" or overlying rock and soil, thus exposing the railway or roadway to daylight

Daylight

Daylight or the light of day is the combination of all direct and indirect sunlight outdoors during the daytime. This includes direct sunlight, diffuse sky radiation, and both of these reflected from the Earth and terrestrial objects. Sunlight scattered or reflected from objects in outer space is...

. This could also be seen as converting the tunnel to a railway or roadway cut

Cut (earthmoving)

In civil engineering, a cut or cutting is where soil or rock material from a hill or mountain is cut out to make way for a canal, road or railway line....

. Tunnels are often daylighted to improve vertical or horizontal clearances, for example to accommodate double-stack container trains

Intermodal freight transport

Intermodal freight transport involves the transportation of freight in an intermodal container or vehicle, using multiple modes of transportation , without any handling of the freight itself when changing modes. The method reduces cargo handling, and so improves security, reduces damages and...

 or electrifying rail lines, where increasing the size of the tunnel bore would be impractical.

List of Daylighted Tunnels

• United States of America
  • Auburn Tunnel
    Auburn Tunnel
    Auburn Tunnel was a 19th century canal tunnel built for the Schuylkill Canal, near Auburn, Pennsylvania. Auburn Tunnel was the first transportation tunnel built in the United States....
    
     on the Schuylkill Canal
    Schuylkill Canal
    Schuylkill Canal is the common, but technically inaccurate, name for the Schuylkill Navigation, a 19th-century commercial waterway in and along the Schuylkill River in the U.S. state of Pennsylvania. The "canal" was actually a system of interconnected man-made canals and slack-water pools in the...
    
    , daylighted in 1857
  • Tunnel No. 5 on the Alaska Railroad
    Alaska Railroad
    The Alaska Railroad is a Class II railroad which extends from Seward and Whittier, in the south of the state of Alaska, in the United States, to Fairbanks , and beyond to Eielson Air Force Base and Fort Wainwright in the interior of that state...
    
    's Seward-Anchorage line
  • Tunnel No. 5 on the Virginia & Truckee Railroad
    Virginia and Truckee Railroad
    The Virginia and Truckee Railroad was built to serve the Comstock Lode mining communities of northwestern Nevada. At its height, the railroad's route ran from Reno south to Carson City, Nevada. In Carson City, the...
    
     at Nevada S.R. 341
    Nevada State Route 341
    State Route 341 is a state highway in western Nevada connecting US 50 near Dayton to Reno via Virginia City. Commonly known as the Virginia City Highway, or Geiger Grade north of Virginia City, the route has origins dating back to the 1860s.-Route description:Nevada State Route 341 begins at a...
    
     near Virginia City
    Virginia City, Nevada
    Virginia City is a census-designated place that is the county seat of Storey County, Nevada. It is part of the Reno–Sparks Metropolitan Statistical Area. The population was 855 at the 2010 Census.- History :...
    
    
  • The Gwynedd Cut on the North Pennsylvania Railroad
    North Pennsylvania Railroad
    North Pennsylvania Railroad was a railroad company formed in 1855, and served Philadelphia, Montgomery County, Bucks County and Northampton County, Pennsylvania.-History:...
    
    , near North Wales, Pennsylvania
    North Wales, Pennsylvania
    North Wales is a borough in Montgomery County, Pennsylvania, United States. It is a suburb of Philadelphia, Pennsylvania, and is one of the three historic population centers that make up the North Penn Valley...
    
    , built as a tunnel between 1853 and 1856, daylighted in 1930 when the Reading Railroad electrified the line

See also

• Cut (earthmoving)
  Cut (earthmoving)
  In civil engineering, a cut or cutting is where soil or rock material from a hill or mountain is cut out to make way for a canal, road or railway line....
  
  
• Cutting (transportation)
• Daylighting (streams)
  Daylighting (streams)
  In urban design and urban planning, daylighting is the redirection of a stream into an above-ground channel. Typically, the goal is to restore a stream of water to a more natural state...