The Thomas Viaduct spans the Patapsco River and Patapsco Valley between

Relay, Maryland Relay, Maryland, or Relay House, Maryland, was formerly an important junction and rail stop on the Baltimore and Ohio Railroad, located west of Baltimore, Maryland. It was the busiest station on the line except for Baltimore itself. A town grew up ...

and

Elkridge, Maryland Elkridge is an unincorporated community and census-designated place (CDP) in Howard County, Maryland, United States. The population was 15,593 at the 2010 census. Founded early in the 18th century, Elkridge is adjacent to two other counties, A ...

, USA. It was commissioned by the

Baltimore and Ohio Railroad The Baltimore and Ohio Railroad was the first common carrier railroad and the oldest railroad in the United States, with its first section opening in 1830. Merchants from Baltimore, which had benefited to some extent from the construction of ...

(B&O); built between July 4, 1833, and July 4, 1835; and named for Philip E. Thomas, the company's first president. It remains the world's oldest multiple arched stone railroad bridge. At its completion, the Thomas Viaduct was the largest railroad bridge in the United States and the country's first multi-span

masonry Masonry is the building of structures from individual units, which are often laid in and bound together by mortar; the term ''masonry'' can also refer to the units themselves. The common materials of masonry construction are bricks, building ...

railroad 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 ...

bridge A bridge is a structure built to span a physical obstacle (such as a body of water, valley, road, or rail) without blocking the way underneath. It is constructed for the purpose of providing passage over the obstacle, which is usually somethi ...

to be built on a curve. In 1964, it was designated as a

National Historic Landmark A National Historic Landmark (NHL) is a building, district, object, site, or structure that is officially recognized by the United States government for its outstanding historical significance. Only some 2,500 (~3%) of over 90,000 places listed ...

. In 2010, the bridge was designated as a National Historic Civil Engineering Landmark by the

American Society of Civil Engineers American(s) may refer to: * American, something of, from, or related to the United States of America, commonly known as the "United States" or "America" ** Americans, citizens and nationals of the United States of America ** American ancestry, pe ...

. The viaduct is now owned and operated by

CSX Transportation CSX Transportation , known colloquially as simply CSX, is a Class I freight railroad operating in the Eastern United States and the Canadian provinces of Ontario and Quebec. The railroad operates approximately 21,000 route miles () of track. ...

and still in use today, making it one of the oldest railroad bridges still in service.

Design

This Roman-arch stone bridge is divided into eight spans. It was designed by

Benjamin Henry Latrobe, II Benjamin Henry Latrobe II (December 19, 1806 – October 19, 1878) was an American civil engineer, best known for his railway bridges, and a railway executive. Personal life Born in Philadelphia, Pennsylvania on December 19, 1806, he was the ...

, 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 image:Brighton Pier, Brighton, East Sussex, England-2Oct2011 (1).jpg, Seaside pleasure pier in Brighton, England. The first seaside piers were built in England in the early 19th century. A pier is a raised structure that rises above a body of ...

widths between the opposite sides of the structure. This problem was solved by having the lateral pier faces laid out on radial lines, making the piers essentially wedge-shaped and fitted to the 4-degree curve. The viaduct was built by John McCartney of

Ohio Ohio () is a state in the Midwestern region of the United States. Of the fifty U.S. states, it is the 34th-largest by area, and with a population of nearly 11.8 million, is the seventh-most populous and tenth-most densely populated. The sta ...

, who received the contract after completing the

Patterson Viaduct The Patterson Viaduct was built by the Baltimore and Ohio Railroad (B&O) as part of its Old Main Line during May to December 1829. The viaduct spanned the Patapsco River at Ilchester, Maryland. It was heavily damaged by a flood in 1866 and subse ...

. Caspar Wever, the railroad's chief of construction, supervised the work. The span of the viaduct is long; the individual arches are roughly in span, with a height of from the water level to the base of the rail. The width at the top of the spandrel wall copings is . The bridge is constructed using a rough-dressed

Maryland Maryland ( ) is a state in the Mid-Atlantic region of the United States. It shares borders with Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware and the Atlantic Ocean to ...

granite Granite () is a coarse-grained (phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies undergro ...

ashlar Ashlar () is finely dressed (cut, worked) stone, either an individual stone that has been worked until squared, or a structure built from such stones. Ashlar is the finest stone masonry unit, generally rectangular cuboid, mentioned by Vitruv ...

from Patapsco River

quarries A quarry is a type of open-pit mine in which dimension stone, rock, construction aggregate, riprap, sand, gravel, or slate is excavated from the ground. The operation of quarries is regulated in some jurisdictions to reduce their envir ...

, known as Woodstock granite. A wooden-floored walkway built for pedestrian and railway employee use is wide and supported by

cast iron Cast iron is a class of iron–carbon alloys with a carbon content more than 2%. Its usefulness derives from its relatively low melting temperature. The alloy constituents affect its color when fractured: white cast iron has carbide impuriti ...

brackets and edged with ornamental cast iron railings. The viaduct contains of masonry and cost $142,236.51, equal to $ today.

History

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 The Inner Harbor is a historic seaport, tourist attraction, and landmark of the city of Baltimore, Maryland. It was described by the Urban Land Institute in 2009 as "the model for post-industrial waterfront redevelopment around the world". Th ...

) at downtown Baltimore and the Baltimore Harbor and Port of the lower river estuary leading southeast 15 miles to flow into the

Chesapeake Bay The Chesapeake Bay ( ) is the largest estuary in the United States. The Bay is located in the Mid-Atlantic (United States), Mid-Atlantic region and is primarily separated from the Atlantic Ocean by the Delmarva Peninsula (including the parts: the ...

. (''See

Baltimore Terminal Subdivision The Baltimore Terminal Subdivision is a railroad line owned and operated by CSX Transportation in the U.S. state of Maryland. The line runs from Baltimore to Halethorpe along the original Baltimore and Ohio Railroad (B&O) line, one of the old ...

and

Old Main Line Subdivision The Old Main Line Subdivision is a railroad line owned and operated by CSX Transportation in the U.S. state of Maryland. The line runs from Relay (outside Baltimore) west to Point of Rocks, and was once the main line of the Baltimore and Ohio Ra ...

.'') In 1835 the

Washington Branch Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered on ...

was constructed, including the Thomas Viaduct. This new line branched at

Relay A relay Electromechanical relay schematic showing a control coil, four pairs of normally open and one pair of normally closed contacts An automotive-style miniature relay with the dust cover taken off A relay is an electrically operated switch ...

, the site of a former

post road A post road is a road designated for the transportation of postal mail. In past centuries, only major towns had a post house and the roads used by post riders or mail coaches to carry mail among them were particularly important ones or, due ...

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 $ today) Viaduct Hotel in 1872. The Gothic combination railroad station and hotel operated until 1938 and was torn down in 1950. When the Thomas Viaduct was completed, a

obelisk An obelisk (; from grc, ὀβελίσκος ; diminutive of ''obelos'', " spit, nail, pointed pillar") is a tall, four-sided, narrow tapering monument which ends in a pyramid-like shape or pyramidion at the top. Originally constructed by Anc ...

with the names of the builder, directors of the railroad, the

architect An architect is a person who plans, designs and oversees the construction of buildings. To practice architecture means to provide services in connection with the design of buildings and the space within the site surrounding the buildings that h ...

(engineer) and others associated with the viaduct was erected at the east end in Relay, by builder John McCartney. 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 Baptism (from grc-x-koine, βάπτισμα, váptisma) is a form of ritual purification—a characteristic of many religions throughout time and geography. In Christianity, it is a Christian sacrament of initiation and adoption, almost inv ...

" them with a pint of

whiskey Whisky or whiskey is a type of distilled alcoholic beverage made from fermented grain mash. Various grains (which may be malted) are used for different varieties, including barley, corn, rye, and wheat. Whisky is typically aged in wooden ...

. Until after the

American Civil War The American Civil War (April 12, 1861 – May 26, 1865; also known by other names) was a civil war in the United States. It was fought between the Union ("the North") and the Confederacy ("the South"), the latter formed by states th ...

, the B&O was the only railroad into

Washington, D.C. ) , image_skyline = , image_caption = Clockwise from top left: the Washington Monument and Lincoln Memorial on the National Mall, United States Capitol, Logan Circle, Jefferson Memorial, White House, Adams Morgan, ...

, thus the Thomas Viaduct was essential for supply trains to reach the capital of the

Union Union commonly refers to: * Trade union, an organization of workers * Union (set theory), in mathematics, a fundamental operation on sets Union may also refer to: Arts and entertainment Music * Union (band), an American rock group ** ''Un ...

during that conflict. To prevent sabotage, the bridge was heavily guarded by Union troops stationed along its length. In 1929, extensive mortar work on the masonry was carried out, and again in 1937. To counteract deterioration of the masonry, the Thomas Viaduct underwent more cosmetic upgrades in 1938 performed by the B&O

Maintenance of Way Maintenance of way (commonly abbreviated to MOW) refers to the maintenance, construction, and improvement of rail infrastructure, including tracks, ballast, grade, and lineside infrastructure such as signals and signs. Track The most fundamen ...

Department. The work consisted primarily to improve 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 added giving more lateral clearance. Little work had been done on the viaduct until the repairs of 1937–1938 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 (''City in a Garden''); I Will , image_map = , map_caption = Interactive Map of Chicago , coordinates = , coordinates_footnotes = , subdivision_type = Country , subdivision_name ...

and the ''

National Limited The ''National Limited'' was the premier train of the Baltimore and Ohio Railroad (B&O) on its route between Jersey City, New Jersey and St. Louis, Missouri, with major station stops in Washington, D.C., and Cincinnati, Ohio. (Buses took passen ...

'' to

St. Louis St. Louis () is the second-largest city in Missouri, United States. It sits near the confluence of the Mississippi and the Missouri Rivers. In 2020, the city proper had a population of 301,578, while the bi-state metropolitan area, which e ...

. With the advent of

Amtrak The National Railroad Passenger Corporation, Trade name, doing business as Amtrak () , is the national Passenger train, passenger railroad company of the United States. It operates inter-city rail service in 46 of the 48 contiguous United Stat ...

on May 1, 1971, B&O ended its passenger train service, except for local Baltimore–Washington commuter trains. In 1986,

CSX CSX Transportation , known colloquially as simply CSX, is a Class I freight railroad operating in the Eastern United States and the Canadian provinces of Ontario and Quebec. The railroad operates approximately 21,000 route miles () of track. ...

acquired the B&O and all of its trackage, including the Thomas Viaduct. Today,

MARC Marc or MARC may refer to: People * Marc (given name), people with the first name * Marc (surname), people with the family name Acronyms * MARC standards, a data format used for library cataloging, * MARC Train, a regional commuter rail system o ...

's "Camden Line" train service runs daily trains over the Viaduct. ''See''

Capital Subdivision The Capital Subdivision is a railroad line owned and operated by CSX Transportation in the U.S. state of Maryland and the District of Columbia. The line runs from near Baltimore, Maryland, southwest to Washington, D.C., along the former Baltimor ...

. 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 Hurricane Agnes in 1972 was the costliest hurricane to hit the United States at the time, causing an estimated $2.1 billion in damage. The hurricane's death toll was 128. The effects of Agnes were widespread, from the Caribbean to Canada, ...

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 Ton is the name of any one of several units of measure. It has a long history and has acquired several meanings and uses. Mainly it describes units of weight. Confusion can arise because ''ton'' can mean * the long ton, which is 2,240 pounds ...

(270

tonne The tonne ( or ; symbol: t) is a unit of mass equal to 1000 kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton to distinguish it from the non-metric units of the short ton ( United State ...

)

diesel locomotive A diesel locomotive is a type of railway locomotive in which the prime mover is a diesel engine. Several types of diesel locomotives have been developed, differing mainly in the means by which mechanical power is conveyed to the driving whee ...

s passengers and heavy

freight Cargo consists of bulk goods conveyed by water, air, or land. In economics, freight is cargo that is transported at a freight rate for commercial gain. ''Cargo'' was originally a shipload but now covers all types of freight, including transp ...

traffic Traffic comprises pedestrians, vehicles, ridden or herded animals, trains, and other conveyances that use public ways (roads) for travel and transportation. Traffic laws govern and regulate traffic, while rules of the road include traffic ...

. The bridge was designated a

on January 28, 1964, and and administratively listed on the

National Register of Historic Places The National Register of Historic Places (NRHP) is the United States federal government's official list of districts, sites, buildings, structures and objects deemed worthy of preservation for their historical significance or "great artistic v ...

on October 15, 1966. In 2010, the bridge designated as a National Historic Civil Engineering Landmark by the

. 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. The Patapsco Heritage Greenway group announced plans to add handrails to the bridge in 2015.

References and footnotes

External links

National Historic Landmark informationThe Thomas Viaduct At Relay Maryland
at archive.org * * - includes 1978 photo
Rasmussen, Frederick N. "Thomas Viaduct celebrates its 175th anniversary in July," ''The Baltimore Sun'', Saturday, June 19, 2010.American Society of Civil Engineers landmark information
*
Many historic and contemporary photos and images of the Thomas Viaduct
{{Authority control Baltimore and Ohio Railroad bridges Bridges completed in 1835 Crossings of the Patapsco River Railroad bridges on the National Register of Historic Places in Maryland CSX Transportation bridges Historic Civil Engineering Landmarks National Historic Landmarks in Maryland Railroad bridges in Maryland Viaducts in the United States Bridges in Baltimore County, Maryland Bridges in Howard County, Maryland Historic American Engineering Record in Maryland Elkridge, Maryland History of rail transportation in the United States Railroad-related National Historic Landmarks National Register of Historic Places in Baltimore County, Maryland Stone arch bridges in the United States 1835 establishments in Maryland

Design

History

See also

References and footnotes

External links