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High Bridge (Coatesville, Pennsylvania)
Encyclopedia
The Coatesville High Bridge is a stone masonry arch
railroad viaduct
that crosses the valley of the West Branch Brandywine Creek
at Coatesville, Pennsylvania
. Built by the Pennsylvania Railroad
between 1902 and 1904, it has ten arches (eight of 78 feet (23.8 m) and two of 88 feet (26.8 m)) and spans a total length of 934 feet (284.7 m), with wing walls extending it to 1287 feet (392.3 m). 78 feet (23.8 m) high, the bridge was built to accommodate four standard gauge
railroad tracks, with a total length of 52 feet (15.8 m).
The Pennsylvania Railroad's Main Line
passes along the north side of Coatesville on the southern slope of the North Valley Hills
. The bridge carries the Main Line across the water gap
cut by the Brandywine, as well as the former Wilmington and Northern Branch of the Reading Railroad and Pennsylvania Route 82
.
bridge in 1867, and that in turn by a wrought iron
Pratt truss in 1890. By the turn of the century, however, the double-track bridge was proving to be a bottleneck in the quadruple-track main line on both sides, and plans were made for a bridge that would carry four tracks across the Brandywine Valley.
bridges since the 1880s, and was constructing others nearby at the time, such as the High Bridge at Downingtown, President A. J. Cassatt
decided in favor of a stone bridge at this location and elsewhere. This reflected the influence of PRR Chief Engineer William H. Brown, who rebuilt many of the railroad's bridges in masonry during his tenure. While more expensive than steel, Brown felt that stone bridges were stronger and more durable, and less expensive to maintain in the long term.
Work on the bridge began in November 1902, locating it slightly to the south of the double-track bridge. The bridge was completed on 1 September 1904 and the main line was realigned to cross it, abandoning the old bridge. The realignment reduced the curvature in the area and completed the PRR's four-track main line from Philadelphia to the Conestoga River
bridge near Lancaster
.
In later years, a concrete
parapet
was added to the bridge and the tops of some arches were reinforced with concrete. Catenary poles were added to the bridge with electrification
in the 1930s. Ownership of the bridge passed, with the rest of the Main Line, to Penn Central in 1968 and Amtrak
in 1976.
Arch
An arch is a structure that spans a space and supports a load. Arches appeared as early as the 2nd millennium BC in Mesopotamian brick architecture and their systematic use started with the Ancient Romans who were the first to apply the technique to a wide range of structures.-Technical aspects:The...
railroad 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...
that crosses the valley of the West Branch Brandywine Creek
West Branch Brandywine Creek
The West Branch Brandywine Creek is a tributary of Brandywine Creek in Chester County, Pennsylvania in the United States.The West Branch Brandywine Creek is born near the community of Honey Brook. It later joins with the East Branch Brandywine Creek in the community of Lenape to form Brandywine...
at Coatesville, Pennsylvania
Coatesville, Pennsylvania
Coatesville is the only city in Chester County, Pennsylvania, United States. The population was 13,100 at the 2010 census. Coatesville is approximately 39 miles west of Philadelphia....
. Built by the Pennsylvania Railroad
Pennsylvania Railroad
The Pennsylvania Railroad was an American Class I railroad, founded in 1846. Commonly referred to as the "Pennsy", the PRR was headquartered in Philadelphia, Pennsylvania....
between 1902 and 1904, it has ten arches (eight of 78 feet (23.8 m) and two of 88 feet (26.8 m)) and spans a total length of 934 feet (284.7 m), with wing walls extending it to 1287 feet (392.3 m). 78 feet (23.8 m) high, the bridge was built to accommodate four standard gauge
Standard gauge
The standard gauge is a widely-used track gauge . Approximately 60% of the world's existing railway lines are built to this gauge...
railroad tracks, with a total length of 52 feet (15.8 m).
The Pennsylvania Railroad's Main Line
Main Line (Pennsylvania Railroad)
The Main Line of the Pennsylvania Railroad was a rail line in the U.S. state of Pennsylvania, connecting Philadelphia with Pittsburgh via Harrisburg...
passes along the north side of Coatesville on the southern slope of the North Valley Hills
Great Valley (Chester County, Pennsylvania)
Great Valley is a west-to-east valley through the center of Chester County, Pennsylvania, USA. It is also sometimes referred to as Chester Valley, and both names are in use throughout the region. The valley stretches from the Schuylkill River in Montgomery County in the east, southwesterly...
. The bridge carries the Main Line across the water gap
Water gap
A water gap is an opening or notch which flowing water has carved through a mountain range. Water gaps often offer a practical route for road and rail transport to cross mountain ridges.- Geology :...
cut by the Brandywine, as well as the former Wilmington and Northern Branch of the Reading Railroad and Pennsylvania Route 82
Pennsylvania Route 82
Pennsylvania Route 82 is a long north–south state highway located in southeast Pennsylvania, USA. The northern terminus is at PA 23 in Elverson...
.
Precursors
The first bridge at the site was built by the Philadelphia and Columbia Railroad in 1832. It was a single-track wood span on stone piers. The bridge was widened to double-track in 1854. This bridge was replaced by a cast ironCast 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...
bridge in 1867, and that in turn by a wrought iron
Wrought iron
thumb|The [[Eiffel tower]] is constructed from [[puddle iron]], a form of wrought ironWrought iron is an iron alloy with a very low carbon...
Pratt truss in 1890. By the turn of the century, however, the double-track bridge was proving to be a bottleneck in the quadruple-track main line on both sides, and plans were made for a bridge that would carry four tracks across the Brandywine Valley.
Construction and history
While the PRR had been using steelSteel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
bridges since the 1880s, and was constructing others nearby at the time, such as the High Bridge at Downingtown, President A. J. Cassatt
Alexander Cassatt
Alexander Johnston Cassatt was the 7th president of the Pennsylvania Railroad , serving from June 9, 1899 to December 28, 1906. Frequently referred to as A. J. Cassatt, the great accomplishment under his stewardship was the planning and construction of tunnels under the Hudson River to finally...
decided in favor of a stone bridge at this location and elsewhere. This reflected the influence of PRR Chief Engineer William H. Brown, who rebuilt many of the railroad's bridges in masonry during his tenure. While more expensive than steel, Brown felt that stone bridges were stronger and more durable, and less expensive to maintain in the long term.
Work on the bridge began in November 1902, locating it slightly to the south of the double-track bridge. The bridge was completed on 1 September 1904 and the main line was realigned to cross it, abandoning the old bridge. The realignment reduced the curvature in the area and completed the PRR's four-track main line from Philadelphia to the Conestoga River
Conestoga River
The Conestoga River, also referred to as Conestoga Creek, is a tributary of the Susquehanna River flowing through the center of Lancaster County, Pennsylvania.-Geography:...
bridge near Lancaster
Lancaster, Pennsylvania
Lancaster is a city in the south-central part of the Commonwealth of Pennsylvania. It is the county seat of Lancaster County and one of the older inland cities in the United States, . With a population of 59,322, it ranks eighth in population among Pennsylvania's cities...
.
In later years, a concrete
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
parapet
Parapet
A parapet is a wall-like barrier at the edge of a roof, terrace, balcony or other structure. Where extending above a roof, it may simply be the portion of an exterior wall that continues above the line of the roof surface, or may be a continuation of a vertical feature beneath the roof such as a...
was added to the bridge and the tops of some arches were reinforced with concrete. Catenary poles were added to the bridge with electrification
Railway electrification system
A railway electrification system supplies electrical energy to railway locomotives and multiple units as well as trams so that they can operate without having an on-board prime mover. There are several different electrification systems in use throughout the world...
in the 1930s. Ownership of the bridge passed, with the rest of the Main Line, to Penn Central in 1968 and 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...
in 1976.