Tunkhannock Viaduct

Tunkhannock Creek Viaduct (also known as the Nicholson Bridge and the Tunkhannock Viaduct) is a concrete deck arch bridge on the Nicholson Cutoff rail line segment of the Norfolk Southern Railway's Sunbury Line that spans Tunkhannock Creek in Nicholson, Pennsylvania.

Opened in 1915 by the Delaware, Lackawanna and Western Railroad (DL&W), the bridge is still used daily for regular through freight service.Norfolk Southern completes acquisition of Delaware & Hudson South Line , PRNewswire, September 18, 2015

The bridge measures long and towers above the creek bed; it stands above bedrock. It was the largest concrete structure in the world at its completion; a half-century later, it still merited "the title of largest concrete bridge in America, if not the world".

In 1975, the American Society of Civil Engineers designated the bridge as a National Historic Civil Engineering Landmark. The bridge was listed on the National Register of Historic Places on May 3, 1977.FEDERAL REGISTER, VOL 42, NO. 85-TUESDAY, MAY 3, 1977, page 22411. ()

History The DL&W built the viaduct as part of its Nicholson Cutoff, which replaced a winding and hilly section of the route between Scranton, Pennsylvania, and Binghamton, New York, reducing travel by —21 minutes of passenger train time or one hour of freight train time. The bridge was designed by the DL&W's Abraham Burton Cohen. Concrete sections of the bridge were designed by architect William Hull Botsford, a 1909 graduate of Cornell University. Botsford did not see the project to completion, as he perished in the sinking of the Titanic in April 1912. 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 by excavating all 11 bridge piers to bedrock, which was up to below ground. In total, excavation for the viaduct removed of material, more than half of that rock.

Almost half of the bulk of the bridge is underground. At mid-construction, of concrete had gone into its substructures, and it was estimated that construction would require of concrete and of steel. The steel estimate proved accurate; the bridge ultimately used a bit less concrete than expected: , making the total weight about .

The bridge was dedicated on November 6, 1915, along with the opening of the Nicholson Cutoff.

Construction photos along with a short history of the bridge were published by the Nicholson Area Library in a brochure in 1976."The Bridge Was Built," Nicholson Area Library, 1976. It was listed on the National Register of Historic Places on April 11, 1977.

Since 1990, the local community has celebrated the building of the bridge on the second Sunday of September with "Nicholson Bridge Day", a street fair, parade, and other activities. The 100th-anniversary celebration was held in September 2015.

Recognition

In 1975 the American Society of Civil Engineers or ASCE designated the bridge as a National Historic Civil Engineering Landmark.Society for Industrial archeology newsletter, November 1975, Vol. 4, No. 6. ASCE noted that at the time of its construction from 1912 to 1915, it was the largest reinforced concrete railroad bridge ever built.Herbert Hands, ASCE news release dated January 22, 1975

ASCE recognized the bridge as "not only a great feat of construction skill" but also a "bold and successful departure from contemporary, conventional concepts of railroad location in that it carried a mainline transversely to the regional drainage pattern, effectively reducing the distance and grade impediments...". At the time, the decision was made to build the bridge out of reinforced concrete, railroad engineers had little experience with this material.

The bridge was also listed on the National Register of Historic Places on May 3, 1977. In 1990, the National Railway Historical Society placed a historical plaque on the structure noting its size as the world's largest concrete bridge, completing the Summit cut-off project for the Delaware, Lackawanna and Western Railroad.

In June 2026, Union Pacific Big Boy No. 4014, the largest and heaviest steam locomotive still in operation, crossed the bridge on its coast-to-coast heritage excursion with Union Pacific and Norfolk Southern units and passenger coaches in tow.

Gallery

Tunkhannock Viaduct

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