Thomas Viaduct

Thomas Viaduct
Thomas Viaduct
Coordinates	39°13′18″N 76°42′48″W / 39.22167°N 76.71333°W
Carries	Railroad
Crosses	Patapsco River
Locale	Elkridge, Maryland
Owner	CSX Transportation
Heritage status	NRHP 66000388
Characteristics
Design	Basket-handle arch bridge
Material	Patapsco granite
Total length	612 feet (187 m)
Width	26 feet 4 inches (8 m)
Height	59 feet (18 m)
Longest span	58 feet (18 m)
No. of spans	8
History
Designer	Benjamin Henry Latrobe, II
Constructed by	John McCartney
Construction start	1833
Opened	July 4, 1835
	Thomas Viaduct, Baltimore & Ohio Railroad
	U.S. National Register of Historic Places
	U.S. National Historic Landmark
Area	0.5 acres (0.20 ha)
NRHP reference No.	66000388
Added to NRHP	October 15, 1966
Location
References

The Thomas Viaduct spans the Patapsco River and Patapsco Valley between Relay, Maryland and Elkridge, Maryland, USA. It was commissioned by the Baltimore and Ohio Railroad (B&O); built between July 4, 1833, and July 4, 1835; and named for Philip E. Thomas, the company's first president.^[3] Some claim it to be the world's oldest multiple arched stone railroad bridge.^[4] However, the Sankey Viaduct on the Liverpool and Manchester Railway was opened in 1830 and finally completed in 1833.

At its completion, the Thomas Viaduct was the largest railroad bridge in the United States^[5] and the country's first multi-span masonry railroad bridge to be built on a curve. In 1964, it was designated as a National Historic Landmark. In 2010, the bridge was designated as a National Historic Civil Engineering Landmark by the American Society of Civil Engineers.

The viaduct is now owned and operated by CSX Transportation and is still in use today, making it one of the oldest railroad bridges still in service.

^ "National Register Information System". National Register of Historic Places. National Park Service. July 9, 2010.
^ Yearby, Jean P. (1984). "Baltimore & Ohio Railroad, Thomas Viaduct" (PDF). Historic American Engineering Record. Washington, D.C.: Library of Congress. Retrieved April 27, 2014.
^ Howard County Historical Society. Images of America, Howard County. p. 17.
^ U.S. Office of Archaeology and Historic Preservation. The National Register of Historic Places, vol, 1, p. 193. (Washington: Government Printing Office, 1972).
^ Maryland Department of Natural Resources Patapsco Valley State Park. "Patapsco Valley State Park History". Archived from the original on August 9, 2007. Retrieved October 3, 2007.