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.
Design
This
Basket-handle arch stone bridge with three centers [6] is divided into eight
spans. It was designed by
Benjamin Henry Latrobe, II, then B&O's assistant engineer and later its chief engineer. The main design problem to overcome was that of constructing such a large bridge on a curve. The design called for several variations in span and
pier widths between the opposite sides of the structure. This problem was solved by laying the lateral pier faces on radial lines, making the piers essentially wedge-shaped and fitted to the 4-degree curve.[2]
The viaduct was built by John McCartney of
Ohio, who received the contract after completing the
Patterson Viaduct. Caspar Wever, the railroad's chief of construction, supervised the work.
The span of the viaduct is 612 feet (187 m) long; the individual arches are roughly 58 feet (18 m) in span, with a height of 59 feet (18 m) from the water level to the base of the rail. The width at the top of the
spandrel wallcopings is 26 feet 4 inches (8 m). The bridge is constructed using a rough-dressed
Marylandgraniteashlar from Patapsco River
quarries, known as
Woodstock granite.[7]
A wooden-floored walkway built for pedestrian and railway employee use is 4 feet (1 m) wide and supported by
cast iron brackets and edged with ornamental cast iron railings. The viaduct contains 24,476 cubic yards (18,713 m3) of masonry and cost $142,236.51, equal to $4,201,024 today.
The Baltimore and Ohio Railroad was one of the oldest railroads in the United States. Construction began on July 4, 1828, with the original route following the upper branch of the
Patapsco River which led west to
Ellicott's Mills (later renamed Ellicott City) from the lower Patapsco which is the "Basin" (now
Inner Harbor) at downtown Baltimore and the
Baltimore Harbor and Port of the lower river estuary leading southeast 15 miles to flow into the
Chesapeake Bay. (See
Baltimore Terminal Subdivision and
Old Main Line Subdivision.) In 1835, the
Washington Branch was constructed, including the Thomas Viaduct. This new line branched at
Relay, the site of a former
post road hotel and changing point for stage horses. The 1830s Relay House served as a hotel until it was replaced by the $50,078.41 (equal to $1,273,661 today) Viaduct Hotel in 1872. The Gothic combination railroad station and hotel operated until 1938 and was torn down in 1950.[8]
When the Thomas Viaduct was completed, a 15-foot (5 m)
obelisk with the names of the builder, directors of the railroad, the
architect (engineer) and others associated with the viaduct was erected at the east end in Relay, by builder John McCartney.[9] On one side the monument reads: The Thomas Viaduct, Commenced July 4, 1833 Finished, July 4, 1835. He also celebrated the completed work by having his men kneel on the deck of the viaduct while mock "
baptizing" them with a pint of
whiskey.
Soon after its completion, two European engineers visited the Viaduct and reported on it. During the period of 1834-1835,
Michel Chevalier was commissioned by the French government to study the North American canal and railroad networks. Chevalier produced a two-volume report, "Histoire et description des voies de communication aux etats-Unis (1840–1841).
[10][11] By 1838,
Franz Anton von Gerstner was the "... leading engineer and scholar of the emerging railroad industry on the continent of Europe."
[12]
Because of railroad growth in the United States, von Gerstner felt the need to study American railroads, including the Baltimore and Ohio Railroad and the Thomas Viaduct.
Until after the
American Civil War, the B&O was the only railroad into
Washington, D.C.; thus, the Thomas Viaduct was essential for supply trains to reach the capital of the
Union during that conflict. Union troops stationed along its length heavily guarded the bridge to prevent sabotage.
In 1929, extensive
mortar work on the masonry was carried out, and again in 1937. To counteract the deterioration of the masonry, the Thomas Viaduct underwent more cosmetic upgrades in 1938 performed by the B&O
Maintenance of Way Department. The work consisted primarily of improving facilities for drainage, relocation of loose arch ring stones, and the application of a
grout mixture to the stone spandrels filling. Nevertheless, the bridge is still indicative of the way in which the B&O
track and major structures were put down in the most permanent manner possible. At an unknown date, railing blocks were removed from the north side of the deck, and a bracketed walkway was added, giving more lateral clearance. Little work had been done on the viaduct until the repairs of 1937 and 1938, which, according to a 1949 report by the Chief Engineer of the B&O, would keep future maintenance to a minimum.
From the 1880s to the 1950s, Thomas Viaduct carried B&O's famed Royal Blue Line passenger trains between New York and Washington. Until the late 1960s, the bridge also carried B&O passenger trains traveling to points west of Washington, such as the Capital Limited to
Chicago and the National Limited to
St. Louis.
With the advent of
Amtrak on May 1, 1971, B&O ended its passenger train service, except for local Baltimore and Washington commuter trains. In 1986,
CSX acquired the B&O and all of its trackage, including the Thomas Viaduct. Today,
MARC's "Camden Line" train service runs daily trains over the Viaduct. SeeCapital Subdivision.
Legacy
"Austrian,
Franz Anton von Gerstner, in his "Zweig- bahn Nach Washington" described the Thomas Viaduct as one of the most beautiful and best-designed bridges in the United States, and went into details. The Frenchman, Michel Chevalier, included it in the few "Travaux d'Art" constructed by railroads in this country."[13] (Cullen,1957)
During design and construction, the Thomas Viaduct was nicknamed "Latrobe's Folly" after the designer Benjamin Latrobe II because, at the time, many doubted that it could even support its own weight. Contrary to these predictions, the Thomas Viaduct survived the great flood of 1868 as well as
Hurricane Agnes in 1972, two floods that wiped out the Patapsco Valley and destroyed nearly everything in their path; and to this day, it continues to carry 300-
ton (270
tonne)
diesel locomotives passengers and heavy
freighttraffic.
The bridge was designated a
National Historic Landmark on January 28, 1964,[14] and administratively listed on the
National Register of Historic Places on October 15, 1966. In 2010, the bridge was designated as a National
Historic Civil Engineering Landmark by the
American Society of Civil Engineers.
In 2014 and 2015, the non-profit historic preservation organization Preservation Howard County placed the Viaduct on its list of the top 10 endangered historic places in Howard County.[15] The Patapsco Heritage Greenway group announced plans to add handrails to the bridge in 2015.[16]
^
abYearby, 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).
^Dilts, James D. (1996). The Great Road: The Building of the Baltimore and Ohio, the Nation's First Railroad, 1828–1853. Palo Alto, CA: Stanford University Press.
ISBN978-0-8047-2629-0.
^Park, John R (2002). Maryland mining heritage guide: including Delaware and the District of Columbia. Miami, FL: Stonerose Pub. Co. pp. 32–33.
ISBN0970669720.
^Howard County Historical Society. Images of America Howard County. p. 116.
^Rice, Laura. Maryland History In Prints 1743-1900. p. 81.
ISBN978-0938420712.
^Robinson, Moncure. "Obituary Notice of Michel Chevalier." (1880): 28-37.
^Kittler, Juraj. "Michel Chevalier and the Saint-Simonian legacy: Early roots of modern cross-national comparative communication research." International Communication Gazette 76.3 (2014): 296-315.
^Gamst, Frederick C. "Franz Anton Ritter von Gerstner, Student of America's Pioneering Railroads." Railroad History 163 (1990): 13-27.
Citing R. von Liliencron, ed., Allgemeine deutsche Biographie 9 (Leipzig, 1879): 67-70; Christian G. Kayser, Bücher-Lexicon, 1841-1846 9 (Leipzig, 1848):