A Steamtown National Historic Site excursion train crosses Tunkhannock Viaduct.
|Locale||Nicholson, Pennsylvania, USA|
|Designer||Abraham Burton Cohen|
|Design||Deck arch bridge|
|Total length||2,375 feet (723.9 m)|
|Longest span||180 feet (54.9 m) each span|
|Number of spans||10|
|Piers in water||13|
|Clearance below||240 feet (73.2 m)|
|Construction begin||May 1912|
November 6, 1915
Location in Pennsylvania
|Area:||3 acres (1.2 ha)|
|Added to NRHP:||April 11, 1977|
Tunkhannock Viaduct (also known as the Nicholson Bridge) is a concrete deck arch bridge that spans the Tunkhannock Creek in Nicholson, Wyoming County, Pennsylvania in the United States. It was the largest[clarification needed] concrete bridge in the U.S. when it opened, and remained so even 50 years later.
The bridge contains about 163,000 cubic yards (125,000 m3) of concrete and 1,250 short tons (1,130 t) of steel. It is 2,375 feet (724 m) long and 240 feet (73 m) tall when measured from the creek bed (300 feet (91 m) tall from the bedrock). The bridge was built as part of the Nicholson Cutoff, which was part of a project of the Lackawanna Railroad to replace a winding and hilly route. This rerouting was built between Scranton, Pennsylvania, and Binghamton, New York. All 13 piers were excavated to bedrock, which was up to 138 feet (42 m) below ground level. Almost half of the bulk of the bridge is underground.
The bridge was built by the Delaware, Lackawanna and Western Railroad and was designed by Abraham Burton Cohen. Other key DL&W staff were G. J. Ray, chief engineer; F. L. Wheaton, engineer of construction; and C. W. Simpson, resident engineer in charge of the construction. The contractor was Flickwir & Bush, including general manager F. M. Talbot and superintendent W. C. Ritner.
Construction on the bridge began in May 1912, and dedication took place on November 6, 1915, with the opening of the Nicholson cutoff. It was listed on the National Register of Historic Places on April 11, 1977. Today, the bridge is owned by the Canadian Pacific Railway and is used daily for regular through freight service, including those of the Norfolk Southern.
Tunkhannock Viaduct, as seen from Route 11
 See also
- Lackawanna cutoff
- List of bridges documented by the Historic American Engineering Record in Pennsylvania
- "National Register Information System". National Register of Historic Places. National Park Service. 2010-07-09.
- Historic American Engineering Record (HAER) No. PA-87. "Erie-Lackawanna Railroad, Tunkhannock Viaduct". Retrieved 5 March 2010.
- Simpson, C. W. (1916). "Construction Methods on Viaducts Of The Lackawanna Railroad Over Tunkhannock and Martins Creeks". Water and Sewage Works (Indianapolis, Indiana: Engineering Publishing Company). 50-51: 94–98. Retrieved November 15, 2012.
- In mid-construction, the estimated amounts of material to be required were 169,000 cubic yards (129,000 m3) of concrete and 1,140 short tons (1,030 t) of steel, as recorded in "Progress of Tunkhannock Viaduct Construction on D., L. & W. Relocation," Engineering Record 68, No. 22 (29 Nov. 1913): 594.
- "The Nicholson Bridge".
- "Northeast Pennsylvania, Nicholson Viaduct".
 Further reading
- Plowden, David (2002). Bridges: The Spans of North America. New York, NY: W.W. Norton and Company.
- "Tunkhannock Viaduct". ASCE History and Heritage of Civil Engineering. Retrieved 2009-11-02.
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