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Safe Harbor Trestle
The Safe Harbor Bridge also known as the Safe Harbor Trestle, Port Road Bridge and the Enola Low Grade Line (A&S Railroad) Steel Trestle is a steel deck truss trestle that spans the Conestoga River at Safe Harbor, Pennsylvania near the Susquehanna River for the Port Road Branch and the former Columbia and Port Deposit Railroad along the Susquehanna River. History and notable features This bridge was built in 1905 for the Atglen and Susquehanna Branch (A&S), also known as the "Low Grade Branch", of the Pennsylvania Railroad (PRR). There is one more bridge at this site, the Safe Harbor Dam access road bridge. The lower span was raised in 1930, concurrent with the construction of the Safe Harbor Dam. In 1976 the PRR lines became part of Conrail, which abandoned the A&S branch in 1989. The tracks were removed from the upper bridge in 1990. The upper portion has been repurposed to serve as part of the Enola Low Grade Trail. See also *List of bridges documented by the Historic A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conestoga River
The Conestoga River, also referred to as Conestoga Creek, is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map, accessed August 8, 2011 tributary of the Susquehanna River flowing through the center of Lancaster County, Pennsylvania, United States. Geography Its headwaters rise mostly in southern Berks County and northeastern Lancaster County, in an area known as "Bortz's Swamp" or "Penngall Field" (a small area rises in Chester County). The East Branch and West Branch of the Conestoga join to form the main river just north of Morgantown, and the stream flows from northeast to southwest for more than , passing close to the center of Lancaster and ending at Safe Harbor along the Susquehanna River, approximately north of the Pennsylvania- Maryland state line. The principal tributaries of the Conestoga River are Cocalico Creek, Mill Creek, and Little Conestoga Creek; they drain into the Conestoga River watershed in the orde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Safe Harbor Dam
The Safe Harbor Dam (also Safe Harbor Hydroelectric Station) is a concrete gravity dam, with an associated hydroelectric power station, on the lower Susquehanna River. It is the most northerly and last of three Great Depression- era public electrification projects' hydroelectric dams, and was constructed between April 1, 1930 and December 7, 1931. It created a long and relatively shallow lake, known as Lake Clarke, along the upper stretch of the Conejohela Valley. The creation of the lake shrank the upper Conejohela Flats in size. Base terrains The mixed marshy terrain of the Conejohela Valley contained rapids and small waterfalls, wetlands, and thick woods along both sides of the river within a ten-year floodplain which saw annual inundations all the way down into Maryland at the headwaters of Chesapeake Bay, and experienced catastrophic floods regularly (the meaning of a ten-year floodplain). The varied terrain created many interface zones biologically nurturing a great many ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Girder Bridges In The United States
A girder () is a support beam used in construction. It is the main horizontal support of a structure which supports smaller beams. Girders often have an I-beam cross section composed of two load-bearing ''flanges'' separated by a stabilizing ''web'', but may also have a box shape, Z shape, or other forms. Girders are commonly used to build bridges. A girt is a vertically aligned girder placed to resist shear loads. Small steel girders are rolled into shape. Larger girders (1 m/3 feet deep or more) are made as plate girders, welded or bolted together from separate pieces of steel plate. The Warren type girder replaces the solid web with an open latticework truss between the flanges. This arrangement combines strength with economy of materials, minimizing weight and thereby reducing loads and expense. Patented in 1848 by its designers James Warren and Willoughby Theobald Monzani, its structure consists of longitudinal members joined only by angled cross-members, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steel Bridges In The United States
Steel is an alloy made up of iron with added carbon to improve its strength and fracture resistance compared to other forms of iron. Many other elements may be present or added. Stainless steels that are corrosion- and oxidation-resistant typically need an additional 11% chromium. Because of its high tensile strength and low cost, steel is used in buildings, infrastructure, tools, ships, trains, cars, machines, electrical appliances, weapons, and rockets. Iron is the base metal of steel. Depending on the temperature, it can take two crystalline forms (allotropic forms): body-centred cubic and face-centred cubic. The interaction of the allotropes of iron with the alloying elements, primarily carbon, gives steel and cast iron their range of unique properties. In pure iron, the crystal structure has relatively little resistance to the iron atoms slipping past one another, and so pure iron is quite ductile, or soft and easily formed. In steel, small amounts of carbon, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pennsylvania Railroad Bridges
Pennsylvania (; (Pennsylvania Dutch: )), officially the Commonwealth of Pennsylvania, is a state spanning the Mid-Atlantic, Northeastern, Appalachian, and Great Lakes regions of the United States. It borders Delaware to its southeast, Maryland to its south, West Virginia to its southwest, Ohio to its west, Lake Erie and the Canadian province of Ontario to its northwest, New York to its north, and the Delaware River and New Jersey to its east. Pennsylvania is the fifth-most populous state in the nation with over 13 million residents as of 2020. It is the 33rd-largest state by area and ranks ninth among all states in population density. The southeastern Delaware Valley metropolitan area comprises and surrounds Philadelphia, the state's largest and nation's sixth most populous city. Another 2.37 million reside in Greater Pittsburgh in the southwest, centered around Pittsburgh, the state's second-largest and Western Pennsylvania's largest city. The state's subsequent fiv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Norfolk Southern Railway Bridges
Norfolk () is a ceremonial and non-metropolitan county in East Anglia in England. It borders Lincolnshire to the north-west, Cambridgeshire to the west and south-west, and Suffolk to the south. Its northern and eastern boundaries are the North Sea, with The Wash to the north-west. The county town is the city of Norwich. With an area of and a population of 859,400, Norfolk is a largely rural county with a population density of 401 per square mile (155 per km2). Of the county's population, 40% live in four major built up areas: Norwich (213,000), Great Yarmouth (63,000), King's Lynn (46,000) and Thetford (25,000). The Broads is a network of rivers and lakes in the east of the county, extending south into Suffolk. The area is protected by the Broads Authority and has similar status to a national park. History The area that was to become Norfolk was settled in pre-Roman times, (there were Palaeolithic settlers as early as 950,000 years ago) with camps along the higher lan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Historic American Engineering Record In Pennsylvania
History (derived ) is the systematic study and the documentation of the human activity. The time period of event before the invention of writing systems is considered prehistory. "History" is an umbrella term comprising past events as well as the memory, discovery, collection, organization, presentation, and interpretation of these events. Historians seek knowledge of the past using historical sources such as written documents, oral accounts, art and material artifacts, and ecological markers. History is not complete and still has debatable mysteries. History is also an academic discipline which uses narrative to describe, examine, question, and analyze past events, and investigate their patterns of cause and effect. Historians often debate which narrative best explains an event, as well as the significance of different causes and effects. Historians also debate the nature of history as an end in itself, as well as its usefulness to give perspective on the problems of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Railroad Bridges In Pennsylvania
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 prepared flat surface, rail vehicles ( rolling stock) are directionally guided by the tracks on which they run. Tracks usually consist of steel rails, installed on sleepers (ties) set in ballast, on which the rolling stock, usually fitted with metal wheels, moves. Other variations are also possible, such as "slab track", in which the rails are fastened to a concrete foundation resting on a prepared subsurface. Rolling stock in a rail transport system generally encounters lower frictional resistance than rubber-tyred road vehicles, so passenger and freight cars (carriages and wagons) can be coupled into longer trains. The operation is carried out by a railway company, providing transport between train stations or freight customer faci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bridges In Lancaster County, Pennsylvania
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 something that is otherwise difficult or impossible to cross. There are many different designs of bridges, each serving a particular purpose and applicable to different situations. Designs of bridges vary depending on factors such as the function of the bridge, the nature of the terrain where the bridge is constructed and anchored, and the material used to make it, and the funds available to build it. The earliest bridges were likely made with fallen trees and stepping stones. The Neolithic people built boardwalk bridges across marshland. The Arkadiko Bridge (dating from the 13th century BC, in the Peloponnese) is one of the oldest arch bridges still in existence and use. Etymology The ''Oxford English Dictionary'' traces the origin of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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