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Horseshoe Curve (Pennsylvania)
Horseshoe Curve is a three-track railroad curve on Norfolk Southern Railway's Pittsburgh Line in Blair County, Pennsylvania. The curve is about long and in diameter. Completed in 1854 by the Pennsylvania Railroad as a way to reduce the westbound grade to the summit of the Allegheny Mountains, it replaced the time-consuming Allegheny Portage Railroad: the only other route across the mountains for large vehicles. The curve was later owned and used by three Pennsylvania Railroad successors: Penn Central, Conrail and Norfolk Southern. Horseshoe Curve was added to the National Register of Historic Places and designated a National Historic Landmark in 1966. It became a National Historic Civil Engineering Landmark in 2004. Horseshoe Curve has long been a tourist attraction. A trackside observation park was completed in 1879. The park was renovated and a visitor center built in the early 1990s. The Railroaders Memorial Museum in Altoona manages the center, which has exhibits pertaini ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orthophoto
An orthophoto, orthophotograph, orthoimage or orthoimagery is an aerial photograph or satellite imagery geometrically corrected ("orthorectified") such that the scale is uniform: the photo or image follows a given map projection. Unlike an uncorrected aerial photograph, an orthophoto can be used to measure true distances, because it is an accurate representation of the Earth's surface, having been adjusted for topographic relief, lens distortion, and camera tilt. Orthophotographs are commonly used in geographic information systems (GIS) as a "map accurate" background image. An orthorectified image differs from "rubber sheeted" rectifications as the latter may accurately locate a number of points on each image but "stretch" the area between so scale may not be uniform across the image. A digital elevation model (DEM) is required to create an accurate orthophoto as distortions in the image due to the varying distance between the camera/sensor and different points on the g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 on the country's National Register of Historic Places are recognized as National Historic Landmarks. A National Historic Landmark District may include contributing properties that are buildings, structures, sites or objects, and it may include non-contributing properties. Contributing properties may or may not also be separately listed. Creation of the program Prior to 1935, efforts to preserve cultural heritage of national importance were made by piecemeal efforts of the United States Congress. In 1935, Congress passed the Historic Sites Act, which authorized the Interior Secretary authority to formally record and organize historic properties, and to designate properties as having "national historical significance", and gave the Nation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Continuous Welded Rail
A railway track (British English and UIC terminology) or railroad track (American English), also known as permanent way or simply track, is the structure on a railway or railroad consisting of the rails, fasteners, railroad ties (sleepers, British English) and ballast (or slab track), plus the underlying subgrade. It enables trains to move by providing a dependable surface for their wheels to roll upon. Early tracks were constructed with wooden or cast iron rails, and wooden or stone sleepers; since the 1870s, rails have almost universally been made from steel. Historical development The first railway in Britain was the Wollaton Wagonway, built in 1603 between Wollaton and Strelley in Nottinghamshire. It used wooden rails and was the first of around 50 wooden-railed tramways built over the next 164 years. These early wooden tramways typically used rails of oak or beech, attached to wooden sleepers with iron or wooden nails. Gravel or small stones were packed around the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minute Of Arc
A minute of arc, arcminute (arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of one degree. Since one degree is of a turn (or complete rotation), one minute of arc is of a turn. The nautical mile (nmi) was originally defined as the arc length of a minute of latitude on a spherical Earth, so the actual Earth circumference is very near . A minute of arc is of a radian. A second of arc, arcsecond (arcsec), or arc second, denoted by the symbol , is of an arcminute, of a degree, of a turn, and (about ) of a radian. These units originated in Babylonian astronomy as sexagesimal subdivisions of the degree; they are used in fields that involve very small angles, such as astronomy, optometry, ophthalmology, optics, navigation, land surveying, and marksmanship. To express even smaller angles, standard SI prefixes can be employed; the milliarcsecond (mas) and microarcsecond (μas), for instance, are commonly used in ast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johnstown, Pennsylvania
Johnstown is a city in Cambria County, Pennsylvania, United States. The population was 18,411 as of the 2020 United States Census, 2020 census. Located east of Pittsburgh, Johnstown is the principal city of the Johnstown, Pennsylvania, Metropolitan statistical area, Metropolitan Statistical Area, which includes Cambria County, Pennsylvania, Cambria County. It is also part of the Johnstown-Somerset, PA Combined Statistical Area, which includes both Cambria and Somerset County, Pennsylvania, Somerset Counties. History Johnstown was settled in 1770. The city has experienced three major floods in its history. The Johnstown Flood of May 31, 1889, occurred after the South Fork Dam collapsed upstream from the city during heavy rains. At least 2,209 people died as a result of the flood and subsequent fire that raged through the debris. Another major flood occurred in 1936. Despite a pledge by President Franklin Delano Roosevelt to make the city flood free, and subsequent work to do ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gallitzin Tunnel
The Gallitzin Tunnels in Gallitzin, Pennsylvania, are a set of three adjacent tunnels through the Allegheny Mountains in western Pennsylvania. They were completed in 1854, 1855, and 1902 by the Pennsylvania Railroad as part of the cross-state route that includes the nearby Horseshoe Curve to the east. Their ownership has since passed to Penn Central Transportation Company, then to Conrail, and most recently to the Norfolk Southern Railway. The tunnels are currently used by Norfolk Southern freight trains and Amtrak ''Pennsylvanian'' passenger trains. History Construction The first tunnel, which is the middle of the three bores through the mountain, was built by the PRR from 1851 to 1854. Originally named "Summit" Tunnel, it is 3,612 feet long at an elevation of 2,167 feet above mean sea level and is known today as the Allegheny Tunnel. The second tunnel, the southernmost of the bores, was constructed by the Commonwealth of Pennsylvania from 1852 to 1855 as part of the New Po ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gallitzin, Pennsylvania
Gallitzin is a borough in Cambria County, Pennsylvania, in the United States. It is bordered by Gallitzin Township and Tunnelhill, all of which sit astride the Eastern continental divide. Tunnel Hill and Gallitzin both are pierced by railroad tunnels shortening the necessary ascent for rails crossing the Allegheny Front onto the Allegheny Plateau which encompasses the towns' terrains. Topping the gaps of the Allegheny, the area is one of only five major breaks in the Appalachians allowing east–west transportation corridors before the advent of 20th century technologies. History Dutch traders and trappers friendly to the Susquehannock may have visited the region about 1620, as the town sits atop a mountain pass through which the ancient Amerindian trails (later renamed the Kittanning Path) transited. The plateau atop the escarpment was the domain of the Iroquoian confederations of the Erie people and the Susquehannock peoples, both sharing the byways and hunting lands of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Geological Survey
The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization's work spans the disciplines of biology, geography, geology, and hydrology. The USGS is a fact-finding research organization with no regulatory responsibility. The agency was founded on March 3, 1879. The USGS is a bureau of the United States Department of the Interior; it is that department's sole scientific agency. The USGS employs approximately 8,670 people and is headquartered in Reston, Virginia. The USGS also has major offices near Lakewood, Colorado, at the Denver Federal Center, and Menlo Park, California. The current motto of the USGS, in use since August 1997, is "science for a changing world". The agency's previous slogan, adopted on the occasion of its hundredt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kittanning Run
450px, Location of Kittanning Gap, along a tributary of the Kittanning Run. The Kittanning Run is one of the several streams draining the Allegheny Plateau, each one cutting an abrupt valley, one of the gaps of the Allegheny— one of several climbing valleys used for centuries by the Amerindian native peoples to pass East-to-West through the Allegheny Front escarpment, a barrier ridge separating the flat highlands plateau, the Appalachian Plateau—from the many barrier ridges making up the local Ridge-and-Valley Appalachians in the Central Pennsylvania heartland. The stream was very likely followed by the Kittanning Path connecting the Indian communities west of the Alleghenies, especially Kittanning Village with the large Indian settlements in the Susquehanna Valley ''and points east'' though the naming of the divergent run up through the Kittanning Gap suggests settlers may have bent the trail up to the plateau along a wider shallower grade, perhaps more suita ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harrisburg, Pennsylvania
Harrisburg is the capital city of the Commonwealth of Pennsylvania, United States, and the county seat of Dauphin County. With a population of 50,135 as of the 2021 census, Harrisburg is the 9th largest city and 15th largest municipality in Pennsylvania. Harrisburg is situated on the east bank of the Susquehanna River. It is the larger principal city of the Harrisburg–Carlisle metropolitan statistical area, also known as the Susquehanna Valley, which had a population of 591,712 as of 2020, making it the fourth most populous metropolitan area in Pennsylvania after the Philadelphia, Pittsburgh, and Lehigh Valley metropolitan areas. Harrisburg played a role in American history during the Westward Migration, the American Civil War, and the Industrial Revolution. During part of the 19th century, the building of the Pennsylvania Canal and later the Pennsylvania Railroad allowed Harrisburg to develop into one of the most industrialized cities in the Northeastern United States. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pittsburgh
Pittsburgh ( ) is a city in the Commonwealth (U.S. state), Commonwealth of Pennsylvania, United States, and the county seat of Allegheny County, Pennsylvania, Allegheny County. It is the most populous city in both Allegheny County and Western Pennsylvania, the List of municipalities in Pennsylvania#Municipalities, second-most populous city in Pennsylvania behind Philadelphia, and the List of United States cities by population, 68th-largest city in the U.S. with a population of 302,971 as of the 2020 United States census, 2020 census. The city anchors the Pittsburgh metropolitan area of Western Pennsylvania; its population of 2.37 million is the largest in both the Ohio Valley and Appalachia, the Pennsylvania metropolitan areas, second-largest in Pennsylvania, and the List of metropolitan statistical areas, 27th-largest in the U.S. It is the principal city of the greater Pittsburgh–New Castle–Weirton combined statistical area that extends into Ohio and West Virginia. Pitts ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horseshoe Curve Map
A horseshoe is a fabricated product designed to protect a horse hoof from wear. Shoes are attached on the palmar surface (ground side) of the hooves, usually nailed through the insensitive hoof wall that is anatomically akin to the human toenail, although much larger and thicker. However, there are also cases where shoes are glued. Horseshoes are available in a wide variety of materials and styles, developed for different types of horse and for the work they do. The most common materials are steel and aluminium, but specialized shoes may include use of rubber, plastic, magnesium, titanium, or copper.Price, Steven D. (ed.) ''The Whole Horse Catalog: Revised and Updated'' New York:Fireside 1998 , pp. 84–87. Steel tends to be preferred in sports in which a strong, long-wearing shoe is needed, such as polo, eventing, show jumping, and western riding events. Aluminium shoes are lighter, making them common in horse racing where a lighter shoe is desired, and often facilitate certa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
