Thomas Viaduct
Encyclopedia
The Thomas Viaduct spans the Patapsco River
and Patapsco Valley between Relay
and Elkridge, Maryland
, USA. It is the first multi-span masonry
railroad bridge
in the United States
to be built on a curve. Construction of the bridge commenced on July 4, 1833, and was completed on July 4, 1835.
The Thomas Viaduct was the largest bridge in the nation in its day and today it remains the world's largest bridge of its kind, as well as the world's oldest multiple arched stone railroad bridge. It was named for Philip E. Thomas
, the first president of the Baltimore and Ohio Railroad
(B&O). Until after the American Civil War
, the B&O was the only railroad into Washington
, thus the Thomas Viaduct was essential for supply trains to reach the capital of the Union
during that conflict. To prevent sabotage, the bridge was heavily guarded by Union troops stationed along its length. The viaduct
is now owned and operated by CSX Transportation
and still in use today, making it one of the oldest railroad bridges still in service.
is divided into eight spans
. It was designed by Benjamin Henry Latrobe, II
, then B&O's assistant engineer, later the chief engineer and built by John McCartney of Ohio
under the supervision of Caspar Wever, the railroad's chief of construction. McCartney received the contract after the successful completion of the Patterson Viaduct
. 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 having the lateral pier faces laid out on radial lines making the piers essentially wedge-shaped and fitted to the 4 degree curve.
The span of the viaduct is 612 ft (187 m) long; the individual arches are roughly 58 ft (18 m) in span, with a height of 59 ft (18.8 m) from the water level to the base of the rail. The width at the top of the spandrel wall copings
is 26 ft, 4 in.(8.03 m). The bridge is constructed using rough-dressed Maryland
granite
ashlar
from Patapsco River quarries
. A wooden-floored walkway built for pedestrian and railway employee use is four feet 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, an estimated $2,769,917.36 in 2007 dollars..
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 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.
The Baltimore and Ohio Railroad was one of the oldest railroads in the United States. Construction began on July 4, 1828, the original route followed the Patapsco River to Ellicott's Mills
(later renamed Ellicott City.) (See Baltimore Terminal Subdivision and Old Main Line Subdivision.) In 1835 the Washington Branch was constructed. This new line branched at Relay, the site of a former post road
hotel and changing point for stage horses. The Relay House served as a hotel until it was replaced by the Viaduct Hotel. The main line was rerouted in 1868 since a flood destroyed the Patterson Viaduct
, which previously carried the main line over the Patapsco. Since then, Thomas Viaduct has carried entirely the railroad's freight and passenger traffic between Baltimore and Washington.
During the 1880s–1950s, Thomas Viaduct carried B&O's famed Royal Blue Line passenger trains between New York and Washington, and, until the late 1960s, B&O passenger trains to points west of Washington, such as the Capital Limited to Chicago
and the National Limited
to St. Louis
. In 1986, CSX
acquired the B&O and all of its trackage which included the Thomas Viaduct. With the advent of Amtrak
on May 1, 1971, all B&O passenger train service was discontinued, except for local Baltimore–Washington commuter trains, which continue to operate on a daily basis over Thomas Viaduct as MARC
's "Camden Line" train service under contract with CSX Transportation. See Capital Subdivision.
When the structure was completed, a fifteen-foot (4.6 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. 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.
During design and construction, the Thomas Viaduct was nicknamed "Latrobe's Folly" after the designer Benjamin Latrobe, because at the time many doubted that it could even support its own weight. Yet it has proved them all wrong, 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 locomotive
s passengers and heavy freight traffic
.
on January 28, 1964, and administratively listed on the National Register of Historic Places
on October 15, 1966. The bridge has also been named a National Historic Civil Engineering Landmark by the American Society of Civil Engineers (ASCE).
Patapsco River
The Patapsco River is a river in central Maryland which flows into Chesapeake Bay. The river's tidal portion forms the harbor for the city of Baltimore...
and Patapsco Valley between Relay
Arbutus, Maryland
As of the 2010 Census Arbutus had a population of 20,583. The racial and ethnic compositon of the population was 76.6% non-Hispanic white, 9.5% non-Hispanic black, 0.2% Native American, 2.1% Asian Indian, 6.5% other Asian, 0.1% Pacific Islander, 0.2% non-Hispanic from some other race, 2.3% from...
and Elkridge, Maryland
Elkridge, Maryland
Elkridge is a census-designated place in Howard County, Maryland, United States. The population was 22,042 at the 2000 census. Founded early in the 18th century, Elkridge is located at the confluence of three counties, the other two being Anne Arundel and Baltimore counties...
, USA. It is the first multi-span masonry
Masonry
Masonry is the building of structures from individual units laid in and bound together by mortar; the term masonry can also refer to the units themselves. The common materials of masonry construction are brick, stone, marble, granite, travertine, limestone; concrete block, glass block, stucco, and...
railroad bridge
Bridge
A bridge is a structure built to span physical obstacles such as a body of water, valley, or road, for the purpose of providing passage over the obstacle...
in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
to be built on a curve. Construction of the bridge commenced on July 4, 1833, and was completed on July 4, 1835.
The Thomas Viaduct was the largest bridge in the nation in its day and today it remains the world's largest bridge of its kind, as well as the world's oldest multiple arched stone railroad bridge. It was named for Philip E. Thomas
Philip E. Thomas
Philip Evan Thomas was the first president of the Baltimore and Ohio Railroad from 1827-1836. He has been referred to as "The Father of American Railways." The Thomas Viaduct bridge in Relay, Maryland was named after him....
, the first president of the Baltimore and Ohio Railroad
Baltimore and Ohio Railroad
The Baltimore and Ohio Railroad was one of the oldest railroads in the United States and the first common carrier railroad. It came into being mostly because the city of Baltimore wanted to compete with the newly constructed Erie Canal and another canal being proposed by Pennsylvania, which...
(B&O). Until after the American Civil War
American Civil War
The American Civil War was a civil war fought in the United States of America. In response to the election of Abraham Lincoln as President of the United States, 11 southern slave states declared their secession from the United States and formed the Confederate States of America ; the other 25...
, the B&O was the only railroad into Washington
Washington, D.C.
Washington, D.C., formally the District of Columbia and commonly referred to as Washington, "the District", or simply D.C., is the capital of the United States. On July 16, 1790, the United States Congress approved the creation of a permanent national capital as permitted by the U.S. Constitution....
, thus the Thomas Viaduct was essential for supply trains to reach the capital of the Union
Union (American Civil War)
During the American Civil War, the Union was a name used to refer to the federal government of the United States, which was supported by the twenty free states and five border slave states. It was opposed by 11 southern slave states that had declared a secession to join together to form the...
during that conflict. To prevent sabotage, the bridge was heavily guarded by Union troops stationed along its length. The viaduct
Viaduct
A viaduct is a bridge composed of several small spans. The term viaduct is derived from the Latin via for road and ducere to lead something. However, the Ancient Romans did not use that term per se; it is a modern derivation from an analogy with aqueduct. Like the Roman aqueducts, many early...
is now owned and operated by CSX Transportation
CSX Transportation
CSX Transportation operates a Class I railroad in the United States known as the CSX Railroad. It is the main subsidiary of the CSX Corporation. The company is headquartered in Jacksonville, Florida, and owns approximately 21,000 route miles...
and still in use today, making it one of the oldest railroad bridges still in service.
Design
This Roman-arch stone bridgeArch bridge
An arch bridge is a bridge with abutments at each end shaped as a curved arch. Arch bridges work by transferring the weight of the bridge and its loads partially into a horizontal thrust restrained by the abutments at either side...
is divided into eight spans
Span (architecture)
Span is the distance between two intermediate supports for a structure, e.g. a beam or a bridge.A span can be closed by a solid beam or of a rope...
. It was designed by Benjamin Henry Latrobe, II
Benjamin Henry Latrobe, II
Benjamin Henry Latrobe, II was an American civil engineer, best known for his railway bridges.He was the son of Benjamin Latrobe, architect of the United States Capitol and the Basilica of the Assumption. The junior Latrobe was born in Philadelphia, Pennsylvania, and was educated in Baltimore,...
, then B&O's assistant engineer, later the chief engineer and built by John McCartney of Ohio
Ohio
Ohio is a Midwestern state in the United States. The 34th largest state by area in the U.S.,it is the 7th‑most populous with over 11.5 million residents, containing several major American cities and seven metropolitan areas with populations of 500,000 or more.The state's capital is Columbus...
under the supervision of Caspar Wever, the railroad's chief of construction. McCartney received the contract after the successful completion of the Patterson Viaduct
Patterson Viaduct
The Patterson Viaduct, heavily damaged by a flood in 1866, spanned the Patapsco River at Ilchester, Maryland. Built from May to December 1829, the viaduct was part of the Old Main Line of the Baltimore and Ohio Railroad. It was constructed in the first building phase of the railroad, which...
. 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
Pier (architecture)
In architecture, a pier is an upright support for a superstructure, such as an arch or bridge. Sections of wall between openings function as piers. The simplest cross section of the pier is square, or rectangular, although other shapes are also common, such as the richly articulated piers of Donato...
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 span of the viaduct is 612 ft (187 m) long; the individual arches are roughly 58 ft (18 m) in span, with a height of 59 ft (18.8 m) from the water level to the base of the rail. The width at the top of the spandrel wall copings
Coping (architecture)
Coping , consists of the capping or covering of a wall.A splayed or wedge coping slopes in a single direction; a saddle coping slopes to either side of a central high point....
is 26 ft, 4 in.(8.03 m). The bridge is constructed using rough-dressed Maryland
Maryland
Maryland is a U.S. state located in the Mid Atlantic region of the United States, bordering Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware to its east...
granite
Granite
Granite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite usually has a medium- to coarse-grained texture. Occasionally some individual crystals are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic...
ashlar
Ashlar
Ashlar is prepared stone work of any type of stone. Masonry using such stones laid in parallel courses is known as ashlar masonry, whereas masonry using irregularly shaped stones is known as rubble masonry. Ashlar blocks are rectangular cuboid blocks that are masonry sculpted to have square edges...
from Patapsco River quarries
Quarry
A quarry is a type of open-pit mine from which rock or minerals are extracted. Quarries are generally used for extracting building materials, such as dimension stone, construction aggregate, riprap, sand, and gravel. They are often collocated with concrete and asphalt plants due to the requirement...
. A wooden-floored walkway built for pedestrian and railway employee use is four feet wide and supported by cast iron
Cast iron
Cast iron is derived from pig iron, and while it usually refers to gray iron, it also identifies a large group of ferrous alloys which solidify with a eutectic. The color of a fractured surface can be used to identify an alloy. White cast iron is named after its white surface when fractured, due...
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, an estimated $2,769,917.36 in 2007 dollars..
Renovations
In 1929, extensive mortarMortar (masonry)
Mortar is a workable paste used to bind construction blocks together and fill the gaps between them. The blocks may be stone, brick, cinder blocks, etc. Mortar becomes hard when it sets, resulting in a rigid aggregate structure. Modern mortars are typically made from a mixture of sand, a binder...
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 Department. The work consisted primarily to improve facilities for drainage, relocation of loose arch ring stones and the application of a grout
Grout
Grout is a construction material used to embed rebars in masonry walls, connect sections of pre-cast concrete, fill voids, and seal joints . Grout is generally composed of a mixture of water, cement, sand, often color tint, and sometimes fine gravel...
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.
Brief history of the B&O route
Ellicott City, Maryland
Ellicott City is an unincorporated community and census-designated place in Howard County, Maryland, United States. It is part of the Baltimore-Washington Metropolitan Area. The population was 65,834 at the 2010 census. It is the county seat of Howard County...
(later renamed Ellicott City.) (See Baltimore Terminal Subdivision and Old Main Line Subdivision.) In 1835 the Washington Branch was constructed. This new line branched at Relay, the site of a former post road
Post road
For other uses, see 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 to the special attention...
hotel and changing point for stage horses. The Relay House served as a hotel until it was replaced by the Viaduct Hotel. The main line was rerouted in 1868 since a flood destroyed the Patterson Viaduct
Patterson Viaduct
The Patterson Viaduct, heavily damaged by a flood in 1866, spanned the Patapsco River at Ilchester, Maryland. Built from May to December 1829, the viaduct was part of the Old Main Line of the Baltimore and Ohio Railroad. It was constructed in the first building phase of the railroad, which...
, which previously carried the main line over the Patapsco. Since then, Thomas Viaduct has carried entirely the railroad's freight and passenger traffic between Baltimore and Washington.
During the 1880s–1950s, Thomas Viaduct carried B&O's famed Royal Blue Line passenger trains between New York and Washington, and, until the late 1960s, B&O passenger trains to points west of Washington, such as the Capital Limited to Chicago
Chicago
Chicago is the largest city in the US state of Illinois. With nearly 2.7 million residents, it is the most populous city in the Midwestern United States and the third most populous in the US, after New York City and Los Angeles...
and the National Limited
National Limited
The National Limited was the premier train of the Baltimore and Ohio Railroad on its route between New York City and St. Louis, Missouri, with major station stops in Washington, D.C., and Cincinnati, Ohio. The all-Pullman version of the National Limited was introduced by the B&O on April 26,...
to St. Louis
St. Louis, Missouri
St. Louis is an independent city on the eastern border of Missouri, United States. With a population of 319,294, it was the 58th-largest U.S. city at the 2010 U.S. Census. The Greater St...
. In 1986, CSX
CSX Transportation
CSX Transportation operates a Class I railroad in the United States known as the CSX Railroad. It is the main subsidiary of the CSX Corporation. The company is headquartered in Jacksonville, Florida, and owns approximately 21,000 route miles...
acquired the B&O and all of its trackage which included the Thomas Viaduct. With the advent of Amtrak
Amtrak
The National Railroad Passenger Corporation, doing business as Amtrak , is a government-owned corporation that was organized on May 1, 1971, to provide intercity passenger train service in the United States. "Amtrak" is a portmanteau of the words "America" and "track". It is headquartered at Union...
on May 1, 1971, all B&O passenger train service was discontinued, except for local Baltimore–Washington commuter trains, which continue to operate on a daily basis over Thomas Viaduct as MARC
MARC Train
MARC , known prior to 1984 as Maryland Rail Commuter Service, is a regional rail system comprising three lines in the Baltimore-Washington Metropolitan Area. MARC is administered by the Maryland Transit Administration , a Maryland Department of Transportation agency, and is operated under contract...
's "Camden Line" train service under contract with CSX Transportation. See Capital Subdivision.
A testament through time
Obelisk
An obelisk is a tall, four-sided, narrow tapering monument which ends in a pyramid-like shape at the top, and is said to resemble a petrified ray of the sun-disk. A pair of obelisks usually stood in front of a pylon...
with the names of the builder, directors of the railroad, the architect
Architect
An architect is a person trained in the planning, design and oversight of the construction of buildings. To practice architecture means to offer or render services in connection with the design and construction of a building, or group of buildings and the space within the site surrounding the...
(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
In Christianity, baptism is for the majority the rite of admission , almost invariably with the use of water, into the Christian Church generally and also membership of a particular church tradition...
" them with a pint of whiskey.
During design and construction, the Thomas Viaduct was nicknamed "Latrobe's Folly" after the designer Benjamin Latrobe, because at the time many doubted that it could even support its own weight. Yet it has proved them all wrong, the Thomas Viaduct survived the great flood of 1868 as well as Hurricane Agnes
Hurricane Agnes
Hurricane Agnes was the first tropical storm and first hurricane of the 1972 Atlantic hurricane season. A rare June hurricane, it made landfall on the Florida Panhandle before moving northeastward and ravaging the Mid-Atlantic region as a tropical storm...
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
The ton is a unit of measure. It has a long history and has acquired a number of meanings and uses over the years. It is used principally as a unit of weight, and as a unit of volume. It can also be used as a measure of energy, for truck classification, or as a colloquial term.It is derived from...
(270 tonne
Tonne
The tonne, known as the metric ton in the US , often put pleonastically as "metric tonne" to avoid confusion with ton, is a metric system unit of mass equal to 1000 kilograms. The tonne is not an International System of Units unit, but is accepted for use with the SI...
) diesel locomotive
Diesel locomotive
A diesel locomotive is a type of railroad locomotive in which the prime mover is a diesel engine, a reciprocating engine operating on the Diesel cycle as invented by Dr. Rudolf Diesel...
s passengers and heavy freight traffic
Traffic
Traffic on roads may consist of pedestrians, ridden or herded animals, vehicles, streetcars and other conveyances, either singly or together, while using the public way for purposes of travel...
.
Historical landmark
The bridge was designated a National Historic LandmarkNational Historic Landmark
A National Historic Landmark is a building, site, structure, object, or district, that is officially recognized by the United States government for its historical significance...
on January 28, 1964, and administratively listed on the National Register of Historic Places
National Register of Historic Places
The National Register of Historic Places is the United States government's official list of districts, sites, buildings, structures, and objects deemed worthy of preservation...
on October 15, 1966. The bridge has also been named a National Historic Civil Engineering Landmark by the American Society of Civil Engineers (ASCE).
See also
- Patterson ViaductPatterson ViaductThe Patterson Viaduct, heavily damaged by a flood in 1866, spanned the Patapsco River at Ilchester, Maryland. Built from May to December 1829, the viaduct was part of the Old Main Line of the Baltimore and Ohio Railroad. It was constructed in the first building phase of the railroad, which...
- one of John McCartney's earlier works. - Bloede dam - a historical hydroelectric dam located within the same park as the Thomas Viaduct.
External links
- National Historic Landmark information
- Baltimore & Ohio Railroad, Thomas Viaduct, Spanning Patapsco River, Elkridge, Howard County, MD: 18 photos, 4 data pages, and 2 photo caption pages at Historic American Building Survey
- Thomas Viaduct Description at Maryland Historical Trust - 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 information - includes 1937 photo