Daylighting a

tunnel A tunnel is an underground passageway, dug through surrounding soil, earth or rock, and enclosed except for the entrance and exit, commonly at each end. A pipeline is not a tunnel, though some recent tunnels have used immersed tube cons ...

is to remove its "roof" of overlying rock and soil, exposing the

railway Rail transport (also known as train transport) is a means of transport that transfers passengers and goods on wheeled vehicles running on rails, which are incorporated in tracks. In contrast to road transport, where the vehicles run on a pre ...

roadway A carriageway (British English) or roadway (North American English) consists of a width of road on which a vehicle is not restricted by any physical barriers or separation to move laterally. A carriageway generally consists of a number of tra ...

daylight Daylight is the combination of all direct and indirect sunlight during the daytime. This includes direct sunlight, diffuse sky radiation, and (often) both of these reflected by Earth and terrestrial objects, like landforms and buildings. Sunligh ...

and converting it to a railway or roadway

cut Cut may refer to: Common uses * The act of cutting, the separation of an object into two through acutely-directed force ** A type of wound ** Cut (archaeology), a hole dug in the past ** Cut (clothing), the style or shape of a garment ** Cut (ea ...

. Tunnels are often daylighted to improve vertical or horizontal clearances—for example, to accommodate double-stack container trains or electrifying rail lines, where increasing the size of the tunnel bore is impractical.

List of daylighted tunnels

* New Zealand ** The railway line through the Manawatu Gorge, when constructed in 1891, had five tunnels. Three of these were daylighted in 2008 to allow for the carriage of large containers (the other two tunnels had their floors lowered).The Encyclopedia of New Zealand: Daylighting a Manawatū Gorge tunnel
/ref> * United Kingdom **

Liverpool Lime Street station Liverpool Lime Street is a terminus railway station and the main station serving the city centre of Liverpool. Opened in August 1836, it is the oldest still-operating grand terminus mainline station in the world. A branch of the West Coast M ...

was originally approached through a twin-track tunnel completed in 1836. The tunnel was daylighted in the 1880s, and replaced with a deep four-track

cutting Cutting is the separation or opening of a physical object, into two or more portions, through the application of an acutely directed force. Implements commonly used for wikt:cut, cutting are the knife and saw, or in medicine and science the scal ...

, with only the eastern approaching

Edge Hill railway station Edge Hill railway station is a railway station that serves the district of Edge Hill, Liverpool, England and is one of the oldest railway stations in the world There have been two stations of that name. The first stood a short distance south- ...

remaining as a tunnel. Lime Street Station tunnel remnant seen from Edge Hill Station

* United States of America **

Auburn Tunnel Auburn Tunnel was a 19th-century canal tunnel built for the Schuylkill Canal near Auburn, Pennsylvania. It was the first transportation tunnel in the United States. The tunnel was deliberately added to the canal as a novelty, as the hill it wa ...

on the Schuylkill Canal, daylighted in 1857 ** Tunnel No. 5 on the

Alaska Railroad Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S., ...

's Seward-Anchorage lineF. C. Weeks et al., "Tunnel 'Daylighting' on the Alaska Railroad," ''Transportation Research Record'' No. 1119, ''Geotechnology'' (1987). ** Tunnel No. 5 on the

Virginia & Truckee Railroad The Virginia and Truckee Railroad is a privately owned heritage railroad, headquartered in Virginia City, Nevada. Its private and publicly owned route is long. When first constructed in the 19th century, it was a commercial freight railroad ...

at Nevada S.R. 341 near

Virginia City Virginia City is a census-designated place (CDP) that is the county seat of Storey County, Nevada, and the largest community in the county. The city is a part of the Reno– Sparks Metropolitan Statistical Area. Virginia City developed as a boom ...

** Th
Gwynedd Cut
on the

North Pennsylvania Railroad The North Pennsylvania Railroad was a railroad company which served Philadelphia, Montgomery County, Bucks County and Northampton County in Pennsylvania. It was formed in 1852 and began operation in 1855. The Philadelphia and Reading Railway, ...

, near

North Wales, Pennsylvania North Wales is a borough in Montgomery County, Pennsylvania. It is a suburb of Philadelphia and is one of the three historic population centers that make up the North Penn Valley, which is centered on the borough of Lansdale. It is approximately ...

, built as a tunnel between 1853 and 1856, daylighted in 1930 when the

Reading Railroad The Reading Company ( ) was a Philadelphia-headquartered railroad that provided passenger and commercial rail transport in eastern Pennsylvania and neighboring states that operated from 1924 until its 1976 acquisition by Conrail. Commonly calle ...

electrified the line ** A number of tunnels were open cut for the

National Gateway National Gateway is a multi-stage railroad construction project in the United States promoted by CSX Transportation, a unit of CSX Corporation. It is designed to improve rail connections between ports in the U.S. mid-Atlantic seaboard and the Midw ...

project including: **
Shoo Fly Tunnel
(2012) **
Pinkerton Tunnel
(2012) **
Benford Tunnel
(2012)

References

Tunnel construction {{civil-engineering-stub

List of daylighted tunnels

See also

References