123-718: The Norristown Branch is a railway line in Pennsylvania . It runs 14.6 miles (23.5 km) from a junction with the SEPTA Main Line in North Philadelphia to Norristown, Pennsylvania . It was originally built by the Philadelphia, Germantown and Norristown Railroad (PG&N) in 1834, and was a part of the Reading Company system from 1870 until 1976. Today it is owned by SEPTA and hosts
246-413: A block and tackle arrangement. Lines are divided into sections to limit the scope of an outage and to allow maintenance. To allow maintenance to the overhead line without having to turn off the entire system, the line is broken into electrically separated portions known as "sections". Sections often correspond with tension lengths. The transition from section to section is known as a "section break" and
369-419: A swing bridge . The catenary wire typically comprises messenger wire (also called catenary wire) and a contact wire where it meets the pantograph. The messenger wire is terminated at the portal, while the contact wire runs into the overhead conductor rail profile at the transition end section before it is terminated at the portal. There is a gap between the overhead conductor rail at the transition end section and
492-476: A "Backdoor" connection between different parts, resulting in, amongst other things, a section of the grid de-energised for maintenance being re-energised from the railway substation creating danger. For these reasons, Neutral sections are placed in the electrification between the sections fed from different points in a national grid, or different phases, or grids that are not synchronized. It is highly undesirable to connect unsynchronized grids. A simple section break
615-1045: A Farmer in Pennsylvania, To the Inhabitants of the British Colonies , which were published in the Pennsylvania Chronicle between December 2, 1767, and February 15, 1768. When the Founding Fathers convened in Philadelphia in 1774, 12 colonies sent representatives to the First Continental Congress . The Second Continental Congress , which began in May 1775, authored and signed the Declaration of Independence in Philadelphia, but when Philadelphia fell to
738-766: A century, the Pennsylvania General Assembly met at various places in the Philadelphia area before it began meeting regularly in Independence Hall in Philadelphia for 63 years. However, events such as the Paxton Boys massacres of 1763 had made the legislature aware of the need for a central capital. In 1799, the General Assembly moved to the Lancaster Courthouse. The Pennsylvania General Assembly met in
861-411: A fixed centre point, with the two half-tension lengths expanding and contracting with temperature. Most systems include a brake to stop the wires from unravelling completely if a wire breaks or tension is lost. German systems usually use a single large tensioning pulley (basically a ratchet mechanism) with a toothed rim, mounted on an arm hinged to the mast. Normally the downward pull of the weights and
984-520: A grant that incorporated all lands included in the original Virginia Company of Plymouth Grant and other lands. This grant was in conflict with the Dutch claim for New Netherland , which included parts of today's Pennsylvania. On June 24, 1664, the Duke of York sold the portion of his large grant that included present-day New Jersey to John Berkeley and George Carteret for a proprietary colony. The land
1107-451: A heavy snowstorm, presumably because of a faulty flue . The General Assembly met at a nearby Methodist Church until a new capitol could be built. Following an architectural selection contest, Chicago architect Henry Ives Cobb was asked to design and build a replacement building. However, the legislature had little money to allocate to the project. When they dubbed the roughly finished, somewhat industrial Cobb Capitol building complete,
1230-485: A high electrical potential by connection to feeder stations at regularly spaced intervals along the track. The feeder stations are usually fed from a high-voltage electrical grid . Electric trains that collect their current from overhead lines use a device such as a pantograph , bow collector or trolley pole . It presses against the underside of the lowest overhead wire, the contact wire. Current collectors are electrically conductive and allow current to flow through to
1353-457: A leader in technology and healthcare. Similarly, Philadelphia has a concentration of university expertise. Healthcare, retail, transportation, and tourism are some of the state's growing industries of the postindustrial era. As in the rest of the nation, most residential population growth has occurred in suburban rather than central city areas, although both major cities have had significant revitalization in their downtown areas. Philadelphia anchors
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#17327796635321476-484: A level crossing with the 1,200 V DC Uetliberg railway line ; at many places, trolleybus lines cross the tramway. In some cities, trolleybuses and trams shared a positive (feed) wire. In such cases, a normal trolleybus frog can be used. Alternatively, section breaks can be sited at the crossing point, so that the crossing is electrically dead. Many cities had trams and trolleybuses using trolley poles. They used insulated crossovers, which required tram drivers to put
1599-579: A multiple unit passes over them. In the United Kingdom equipment similar to Automatic Warning System (AWS) is used, but with pairs of magnets placed outside the running rails (as opposed to the AWS magnets placed midway between the rails). Lineside signs on the approach to the neutral section warn the driver to shut off traction power and coast through the dead section. A neutral section or phase break consists of two insulated breaks back-to-back with
1722-734: A new bridge across the Schuylkill to replace the original connection at Swedes Ford. This new connecting line diverged from the Norristown Branch just west of the former PG&N station in Norristown, crossed Barbadoes Island , and made a connection with the Reading main line. The Reading electrified the branch from 16th Street Junction to Elm Street, on what had been part of the Stony Creek Railroad, in 1933. With
1845-404: A pneumatic servo pantograph with only 3 g acceleration. An electrical circuit requires at least two conductors. Trams and railways use the overhead line as one side of the circuit and the steel rails as the other side of the circuit. For a trolleybus or a trolleytruck , no rails are available for the return current, as the vehicles use rubber tyres on the road surface. Trolleybuses use
1968-532: A railway and road bridge between the two locations. This allowed the two railroads to interchange traffic, and some passenger trains of the Reading began using the PG&;N depot at Ninth Street and Green Street. The Philadelphia and Reading Railroad leased the Philadelphia, Germantown and Norristown on December 1, 1870. The company continued to exist on paper, and remained the owner of the line between 16th Street Junction and Norristown, although control now rested with
2091-415: A return path for the current through their wheels, and must instead use a pair of overhead wires to provide both the current and its return path. To achieve good high-speed current collection, it is necessary to keep the contact wire geometry within defined limits. This is usually achieved by supporting the contact wire from a second wire known as the messenger wire or catenary . This wire approximates
2214-414: A rigid overhead wire in their tunnels, while using normal overhead wires in their above ground sections. In a movable bridge that uses a rigid overhead rail, there is a need to transition from the catenary wire system into an overhead conductor rail at the bridge portal (the last traction current pylon before the movable bridge). For example, the power supply can be done through a catenary wire system near
2337-468: A second parallel overhead line for the return, and two trolley poles , one contacting each overhead wire. ( Pantographs are generally incompatible with parallel overhead lines.) The circuit is completed by using both wires. Parallel overhead wires are also used on the rare railways with three-phase AC railway electrification . In the Soviet Union the following types of wires/cables were used. For
2460-467: A short section of line that belongs to neither grid. Some systems increase the level of safety by the midpoint of the neutral section being earthed. The presence of the earthed section in the middle is to ensure that should the transducer controlled apparatus fail, and the driver also fail to shut off power, the energy in the arc struck by the pantograph as it passes to the neutral section is conducted to earth, operating substation circuit breakers, rather than
2583-539: A simpler alternative for moveable overhead power rails. Electric trains coast across the gaps. To prevent arcing, power must be switched off before reaching the gap and usually the pantograph would be lowered. Given limited clearance such as in tunnels , the overhead wire may be replaced by a rigid overhead rail. An early example was in the tunnels of the Baltimore Belt Line , where a Π section bar (fabricated from three strips of iron and mounted on wood)
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#17327796635322706-478: A tilted position into the horizontal position, connecting the conductor rails at the transition end section and the bridge together to supply power. Short overhead conductor rails are installed at tram stops as for the Combino Supra . Trams draw their power from a single overhead wire at about 500 to 750 V DC. Trolleybuses draw from two overhead wires at a similar voltage, and at least one of
2829-701: A tramway. The tramway operated on 600–700 V DC and the railway on 15 kV AC . In the Swiss village of Oberentfelden , the Menziken–Aarau–Schöftland line operating at 750 V DC crosses the SBB line at 15 kV AC; there used to be a similar crossing between the two lines at Suhr but this was replaced by an underpass in 2010. Some crossings between tramway/light rail and railways are extant in Germany. In Zürich , Switzerland, VBZ trolleybus line 32 has
2952-422: Is briefly in contact with both wires). In normal service, the two sections are electrically connected; depending on the system this might be an isolator, fixed contact or a Booster Transformer. The isolator allows the current to the section to be interrupted for maintenance. On overhead wires designed for trolley poles, this is done by having a neutral section between the wires, requiring an insulator. The driver of
3075-849: Is in Duncannon in Perry County . According to the U.S. Department of Housing and Urban Development 's 2022 Annual Homeless Assessment Report , there were an estimated 12,691 homeless people in Pennsylvania. Among Pennsylvania residents, as of 2020, nearly three out of four, 74.5%, are native to the state and were born in Pennsylvania, 18.4% were born in a different U.S. state, 1.5% were born in Puerto Rico , U.S. Island areas, or born abroad to American parent(s), and 5.6% were foreign born. Foreign-born Pennsylvanians are largely from Asia (36.0%), Europe (35.9%), and Latin America (30.6%) with
3198-422: Is in use, standard sizes for contact wire are 100 and 150 mm . The catenary wire is made of copper or copper alloys of 70, 120 or 150 mm . The smaller cross sections are made of 19 strands, whereas the bigger has 37 strands. Two standard configurations for main lines consist of two contact wires of 100 mm and one or two catenary wires of 120 mm , totaling 320 or 440 mm . Only one contact wire
3321-415: Is insufficient to guard against this as the pantograph briefly connects both sections. In countries such as France, South Africa, Australia and the United Kingdom, a pair of permanent magnets beside the rails at either side of the neutral section operate a bogie-mounted transducer on the train which causes a large electrical circuit-breaker to open and close when the locomotive or the pantograph vehicle of
3444-450: Is often used for side tracks. In the UK and EU countries , the contact wire is typically made from copper alloyed with other metals. Sizes include cross-sectional areas of 80, 100, 107, 120, and 150 mm . Common materials include normal and high strength copper, copper-silver, copper-cadmium, copper-magnesium, and copper-tin, with each being identifiable by distinct identification grooves along
3567-421: Is set up so that the vehicle's pantograph is in continuous contact with one wire or the other. For bow collectors and pantographs, this is done by having two contact wires run side by side over the length between 2 or 4 wire supports. A new one drops down and the old one rises up, allowing the pantograph to smoothly transfer from one to the other. The two wires do not touch (although the bow collector or pantograph
3690-610: Is the 33rd-largest by area and has the ninth-highest population density among all states. The largest metropolitan statistical area is the southeastern Delaware Valley , which includes and surrounds Philadelphia, the state's largest and nation's sixth-most populous city. The second-largest metropolitan area, Greater Pittsburgh , is centered in and around Pittsburgh , the state's second-largest city. The state's subsequent five most populous cities are Allentown , Reading , Erie , Scranton , and Bethlehem . Pennsylvania's history of human habitation extends thousands of years before
3813-464: Is the fifth-most populated state in the U.S. after California , Texas , Florida , and New York . In 2019, net migration to other states resulted in a decrease of 27,718, and immigration from other countries resulted in an increase of 127,007. Net migration to Pennsylvania was 98,289. Migration of native Pennsylvanians resulted in a decrease of 100,000 people. 7.2% of the population was foreign-born as of 2021. Pennsylvania's center of population
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3936-1029: Is used only on the Gornergrat Railway and Jungfrau Railway in Switzerland, the Petit train de la Rhune in France, and the Corcovado Rack Railway in Brazil. Until 1976, it was widely used in Italy. On these railways, the two conductors are used for two different phases of the three-phase AC, while the rail was used for the third phase. The neutral was not used. Some three-phase AC railways used three overhead wires. These were an experimental railway line of Siemens in Berlin-Lichtenberg in 1898 (length 1.8 kilometres (1.1 mi)),
4059-805: The British in the Philadelphia campaign , the Continental Congress moved west, where it met at the Lancaster courthouse on Saturday, September 27, 1777, and then to York . In York, the Second Continental Congress adopted the Articles of Confederation , largely authored by Pennsylvania delegate John Dickinson, that formed 13 independent States into a new union. Later, the Constitution was written, and Philadelphia
4182-474: The Canadian province of Ontario to its northwest via Lake Erie . Pennsylvania was founded in 1681 through a royal land grant to William Penn , the son of the state's namesake . Prior to that, between 1638 and 1655, a southeast portion of the state was part of New Sweden , a Swedish Empire colony. Established as a haven for religious and political tolerance, the colonial-era Province of Pennsylvania
4305-746: The Commonwealth of Pennsylvania ( Pennsylvania Dutch : Pennsilfaani ), is a U.S. 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 and the Ohio River to its west, Lake Erie and New York to its north, the Delaware River and New Jersey to its east, and
4428-536: The Declaration of Independence the following year. On December 12, 1787, Pennsylvania was the second state to ratify the U.S. Constitution . In July 1863, the Battle of Gettysburg , fought over three days in and around Gettysburg , was the bloodiest and most decisive battle of the American Civil War , claiming over 50,000 Union and Confederate fatalities and repelling Robert E. Lee 's invasion of
4551-791: The Delaware River in the east and the Susquehanna River in central Pennsylvania. The second tribe, the Susquehannock , spoke an Iroquoian language and were based in Western Pennsylvania from New York state in the north to West Virginia in the southwest, including the Susquehanna, Allegheny , and Monongahela rivers near present-day Pittsburgh . European disease and constant warfare with several neighboring tribes and groups of Europeans weakened these two tribes, and they were grossly outpaced financially as
4674-482: The Delaware River to the east, 80°31' W to the west, and the 42° N to the north, except for a short segment on the western end where a triangle extends north to Lake Erie . The state has five geographical regions: Allegheny Plateau , Ridge and Valley , Atlantic Coastal Plain , Piedmont , and Erie Plain . Pennsylvania's diverse topography produces a variety of climates, though the entire state experiences cold winters and humid summers. Straddling two major zones,
4797-922: The Dominican Republic , China , Mexico , and Vietnam . Overhead line An overhead line or overhead wire is an electrical cable that is used to transmit electrical energy to electric locomotives , electric multiple units , trolleybuses or trams . The generic term used by the International Union of Railways for the technology is overhead line . It is known variously as overhead catenary , overhead contact line ( OCL ), overhead contact system ( OCS ), overhead equipment ( OHE ), overhead line equipment ( OLE or OHLE ), overhead lines ( OHL ), overhead wiring ( OHW ), traction wire , and trolley wire . An overhead line consists of one or more wires (or rails , particularly in tunnels) situated over rail tracks , raised to
4920-884: The Hurons and Iroquois blocked them from proceeding west into Ohio during the Beaver Wars . As they lost numbers and land, the Hurons abandoned much of their western territory and moved closer to the Susquehanna River, and the Iroquois and Mohawk tribes moved further north. Northwest of the Allegheny River was the Iroquoian Petun , who were fragmented into three groups during the Beaver Wars:
5043-628: The Manayunk/Norristown Line commuter rail service. The Philadelphia, Germantown and Norristown Railroad completed its initial line between Philadelphia and Germantown in 1832. The geography of the Wissahickon Creek frustrated plans to build directly from Germantown to Norristown , so the company built west from what is now 16th Street Junction in North Philadelphia . This line reached Manayunk on October 18, 1834, and Norristown on August 15, 1835. The line followed
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5166-896: The Northeast megalopolis and is associated with the Northeastern United States . Pittsburgh is part of the Great Lakes megalopolis and is often associated with the Rust Belt . During the September 11, 2001, terrorist attacks on the United States , the small town of Shanksville, Pennsylvania , received worldwide attention after United Airlines Flight 93 crashed into a field in Stonycreek Township , located 1.75 miles (2.82 km) north of
5289-597: The Reading Company 's final bankruptcy in 1976, the Norristown Branch was conveyed to Conrail and then SEPTA . Early in 2013, SEPTA began to undertake major operational improvements and physical rehabilitation on branch. Central to this project is the replacement of the 80-year-old wayside automatic block signal system with one that displays only in the operating cab , and operates in both directions on both tracks, thereby allowing greater operational flexibility. Two new remotely controlled interlockings are being constructed to facilitate bidirectional operation, one at Miquon,
5412-517: The Secretary of War under President Abraham Lincoln . Control of the machine was subsequently passed on to Cameron's son J. Donald Cameron , whose ineffectiveness resulted in a transfer of power to the more shrewd Matthew Quay and finally to Boies Penrose . The post-Civil War era, known as the Gilded Age , saw the continued rise of industry in Pennsylvania. Pennsylvania was home to some of
5535-791: The Spanish–American War . Pennsylvania was an important industrial center in World War I , and the state provided over 300,000 soldiers for the military. On May 31, 1918, the Pittsburgh Agreement was signed in Pittsburgh to declare the formation of the independent state of Czechoslovakia with future Czechoslovak president Tomáš Masaryk . In 1922, 310,000 Pennsylvania miners joined the UMW General coal strike , which lasted 163 days and shut down most coal mines within
5658-672: The United States . Pennsylvania has 51 miles (82 km) of coastline along Lake Erie and 57 miles (92 km) of shoreline along the Delaware Estuary . Of the original Thirteen Colonies , Pennsylvania is the only state that does not border the Atlantic Ocean . The boundaries of the state are the Mason–Dixon line (39°43' N) to the south, Twelve-Mile Circle on the Pennsylvania- Delaware border,
5781-609: The University of Pennsylvania in Philadelphia . The university, one of nine colonial colleges , was the first college established in Pennsylvania and one of the first in the nation. Today, it is an Ivy League university, which is routinely ranked among the world's best universities. Dickinson College in Carlisle , founded by Benjamin Rush and named after John Dickinson, was the first college founded after Revolutionary War and
5904-431: The county commission and freedom of religion , which were subsequently replicated in many of the Thirteen Colonies . What had been Upland on the Pennsylvania side of the Pennsylvania-Delaware border was renamed Chester County when Pennsylvania instituted its colonial governments on March 4, 1681. Penn signed a peace treaty with Tamanend , leader of the Lenape, which began a long period of friendly relations between
6027-447: The seventh-largest metropolitan area in the country and one of the largest metropolitan areas in the world, and Pittsburgh is the center of the nation's 27th-largest metropolitan areas. As of 2020, the Lehigh Valley in eastern Pennsylvania is the nation's 69th-largest metropolitan area. Pennsylvania also has six additional metropolitan areas that rank among the nation's 200-most populous metropolitan areas. Philadelphia forms part of
6150-463: The tram or trolleybus must temporarily reduce the power draw before the trolley pole passes through, to prevent arc damage to the insulator. Pantograph-equipped locomotives must not run through a section break when one side is de-energized. The locomotive would become trapped, but as it passes the section break the pantograph briefly shorts the two catenary lines. If the opposite line is de-energized, this voltage transient may trip supply breakers. If
6273-420: The 1500 V DC overhead of the railway and the 650 V DC of the trams, called a Tram Square. Several such crossings have been grade separated in recent years as part of the Level Crossing Removal Project . Athens has two crossings of tram and trolleybus wires, at Vas. Amalias Avenue and Vas. Olgas Avenue, and at Ardittou Street and Athanasiou Diakou Street. They use the above-mentioned solution. In Rome , at
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#17327796635326396-514: The 15th U.S. president and was the first president to be born in Pennsylvania. The Battle of Gettysburg , the major turning point of the American Civil War , took place near Gettysburg in July 1863. An estimated 350,000 Pennsylvanians served in the Union Army forces, including 8,600 African American military volunteers . The politics of Pennsylvania were for decades dominated by the financially conservative Republican -aligned Cameron machine , established by U.S. Senator Simon Cameron , later
6519-417: The 45th President of the United States Donald Trump occurred. Pennsylvania is 170 miles (274 km) north to south and 283 miles (455 km) east to west. Of a total 46,055 square miles (119,282 km ), 44,817 square miles (116,075 km ) are land, 490 square miles (1,269 km ) are inland waters, and 749 square miles (1,940 km ) are waters in Lake Erie . It is the 33rd-largest state in
6642-428: The 48 states. The Philadelphia Naval Shipyard served as an important naval base, and Pennsylvania produced important military leaders, including George C. Marshall , Hap Arnold , Jacob Devers , and Carl Spaatz . During the war, over a million Pennsylvanians served in the armed forces, and more Medals of Honor were awarded to Pennsylvanians than to individuals from any other state. The Three Mile Island accident
6765-408: The Americas began, at least two major Native American tribes inhabited Pennsylvania. The first, the Lenape , spoke an Algonquian language and inhabited the eastern region of the state, then known as Lenapehoking . It included most of present-day New Jersey and the Lehigh Valley and Delaware Valley regions in eastern and southeastern Pennsylvania. The Lenape's territory ended somewhere between
6888-543: The Dutch began settling the Delmarva Peninsula by establishing the Zwaanendael Colony on the site of present-day Lewes, Delaware . In 1638, Sweden established the New Sweden Colony in the region of Fort Christina on the site of present-day Wilmington, Delaware . New Sweden claimed and, for the most part, controlled the lower Delaware River region, including parts of present-day Delaware, New Jersey, and Pennsylvania, but settled few colonists there. On March 12, 1664, King Charles II of England gave James, Duke of York
7011-427: The General Assembly refused to occupy the building. In 1901, political and popular indignation prompted a second contest that was restricted to Pennsylvania architects; Joseph Miller Huston of Philadelphia was chosen to design the present Pennsylvania State Capitol that incorporated Cobb's building into a magnificent public work, finished and dedicated in 1907. James Buchanan , a Franklin County native, served as
7134-470: The Hell's Gate Bridge boundary between Amtrak and Metro North 's electrifications) that would never be in-phase. Since a dead section is always dead, no special signal aspect was developed to warn drivers of its presence, and a metal sign with "DS" in drilled-hole letters was hung from the catenary supports. Occasionally gaps may be present in the overhead lines, when switching from one voltage to another or to provide clearance for ships at moveable bridges, as
7257-409: The Netherlands confirmed the English conquest on July 21, 1667, although there were temporary reversions. On September 12, 1672, during the Third Anglo-Dutch War , the Dutch reconquered New York Colony / New Amsterdam , establishing three County Courts, which went on to become original Counties in present-day Delaware and Pennsylvania. The one that later transferred to Pennsylvania was Upland. This
7380-440: The North, leading to the Union's preservation . Throughout the late 19th and 20th centuries, the state's manufacturing-based economy contributed to the development of much of the nation's early infrastructure, including key bridges, skyscrapers , and military hardware used in U.S.-led victories in World War I , World War II , and the Cold War . Pennsylvania's geography is highly diverse. The Appalachian Mountains run through
7503-439: The Petun of New York, the Wyandot of Ohio, and the Tiontatecaga of the Kanawha River in southern West Virginia. South of the Allegheny River was a nation known as Calicua, which may have been part of the Monongahela culture . In the 17th century, the Dutch and the English each claimed both sides of the Delaware River as part of their colonial lands in America. The Dutch were the first to take possession. By June 3, 1631,
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#17327796635327626-563: The Quakers and the Indians. Additional treaties between Quakers and other tribes followed. The Treaty of Shackamaxon of William Penn was never violated. Between 1730 and when the Pennsylvania Colony was shut down by Parliament with the Currency Act in 1764, the Pennsylvania Colony made its own paper money to account for the shortage of actual gold and silver. The paper money was called Colonial Scrip . The Colony issued bills of credit, which were as good as gold or silver coins because of their legal tender status. Since they were issued by
7749-405: The Reading. The Stony Creek Railroad , controlled by the North Pennsylvania Railroad , had built south from Lansdale to Norristown, terminating at Main and Markley, the present site of Norristown–Main Street . This line opened in 1874. The Reading, through the Norristown Junction Railroad , built a connection between the two lines in 1880. Another significant change came in 1903 and opening of
7872-493: The arc either bridging the insulators into a section made dead for maintenance, a section fed from a different phase, or setting up a Backdoor connection between different parts of the country's national grid. On the Pennsylvania Railroad , phase breaks were indicated by a position light signal face with all eight radial positions with lenses and no center light. When the phase break was active (the catenary sections out of phase), all lights were lit. The position light signal aspect
7995-424: The center of the state; the Allegheny and Pocono mountains span much of Northeastern Pennsylvania ; close to 60% of the state is forested . While it has no ocean shoreline, it has 140 miles (225 km) of waterfront along Lake Erie and the tidal Delaware River. Pennsylvania is the fifth-most populous state in the United States , with over 13 million residents as of the 2020 United States census . The state
8118-429: The city's population as of 2000. In the 20th century, as Pennsylvania's historical national and even global leadership in mining largely ceased and its steelmaking and other heavy manufacturing sectors slowed, the state sought to grow its service and other industries to replace the jobs and economic productivity lost from the downturn of these industries. Pittsburgh's concentration of universities has enabled it to be
8241-612: The contact wire, cold drawn solid copper was used to ensure good conductivity . The wire is not round but has grooves at the sides to allow the hangers to attach to it. Sizes were (in cross-sectional area) 85, 100, or 150 mm . To make the wire stronger, 0.04% tin might be added. The wire must resist the heat generated by arcing and thus such wires should never be spliced by thermal means. The messenger (or catenary) wire needs to be both strong and have good conductivity. They used multi-strand wires (or cables) with 19 strands in each cable (or wire). Copper, aluminum, and/or steel were used for
8364-476: The controller into neutral and coast through. Trolleybus drivers had to either lift off the accelerator or switch to auxiliary power. In Melbourne , Victoria, tram drivers put the controller into neutral and coast through section insulators, indicated by insulator markings between the rails. Melbourne has several remaining level crossings between electrified suburban railways and tram lines. They have mechanical switching arrangements (changeover switch) to switch
8487-526: The crossing between Viale Regina Margherita and Via Nomentana, tram and trolleybus lines cross: tram on Viale Regina Margherita and trolleybus on Via Nomentana. The crossing is orthogonal, therefore the typical arrangement was not available. In Milan , most tram lines cross its circular trolleybus line once or twice. Trolleybus and tram wires run parallel in streets such as viale Stelvio, viale Umbria and viale Tibaldi. Some railways used two or three overhead lines, usually to carry three-phase current. This
8610-420: The development of labor unions helped them gain living wages. However, the rise of unions also led to a rise of union busting with several private police forces springing up. Pennsylvania was the location of the first documented organized strike in North America, and Pennsylvania was the location of two hugely prominent strikes, the Great Railroad Strike of 1877 and the Coal Strike of 1902 . The eight-hour day
8733-432: The earliest known signs of human activity in Pennsylvania and perhaps all of North America, including the remains of a civilization that existed over 10,000 years ago and possibly pre-dated the Clovis culture . By 1000 CE, in contrast to their nomadic hunter-gatherer ancestors , the native population of Pennsylvania had developed agricultural techniques and a mixed food economy. By the time European colonization of
8856-563: The east bank of the Schuylkill River and made no crossing of it. The Philadelphia and Reading Railroad extended its main line down the west bank of the Schuylkill in 1838. The Reading served Bridgeport , across the Schuylkill from the PG&N's terminus at Norristown, but no physical connection existed. This was remedied in 1851 when the Swedes Ford Bridge Company , a lessee of the PG&N, constructed
8979-417: The fifth and currently the sixth-largest city after decades of being among the top three. After 1990, as information-based industries became more important in the economy, state and local governments put more resources into the old, well-established public library system. Some localities, however, used new state funding to cut local taxes. New ethnic groups, especially Hispanics and Latinos , began entering
9102-577: The first. At the time, Pennsylvania was the most ethnically and religiously diverse of the thirteen colonies. Because a third of Pennsylvania's population spoke German , the Constitution was presented in German so those citizens could participate in the discussion about it. Reverend Frederick Muhlenberg , a Lutheran minister and the first Speaker of the U.S. House of Representatives , acted as chairman of Pennsylvania's ratifying convention. For half
9225-704: The foundation of the colonial Province of Pennsylvania in 1681. Archaeologists believe the first settlement of the Americas occurred at least 15,000 years ago, during the Last Glacial Period , though it is unclear when humans first inhabited present-day Pennsylvania. Between 10,000 and 16,000 years ago, Native Americans crossed the two continents, arriving in North America . Meadowcroft Rockshelter in Jefferson Township includes
9348-571: The government and not a banking institution, they were interest-free, largely defraying the expense of the government and therefore taxation of the people. It also promoted general employment and prosperity, since the government used discretion and did not issue excessive amounts that inflated the currency. Benjamin Franklin had a hand in creating this currency, whose utility, he said, was never to be disputed. The currency also met with "cautious approval" by Adam Smith . In 1740, Franklin also founded
9471-484: The land be called New Wales, but there were objections to that name, so he recommended Sylvania (from the Latin silva : "forest, woods"). The King named it Pennsylvania (literally "Penn's Woods") in honor of Admiral Penn. The younger Penn was embarrassed at this name, fearing that people would think he had named it after himself, but King Charles would not rename the grant. Penn established a government with two innovations,
9594-630: The largest chocolate manufacturer in North America. Heinz Company was also founded during this period. These huge companies exercised a large influence on the politics of Pennsylvania; as Henry Demarest Lloyd put it, oil baron John D. Rockefeller "had done everything with the Pennsylvania legislature except refine it". Pennsylvania created a Department of Highways and engaged in a vast program of road-building, while railroads continued to see heavy usage. The growth of industry eventually provided middle class incomes to working-class households after
9717-529: The largest steel companies in the world. Andrew Carnegie founded the Carnegie Steel Company in Pittsburgh and Charles M. Schwab founded Bethlehem Steel in Bethlehem . Other titans of industry, including John D. Rockefeller and Jay Gould , also operated in Pennsylvania. In the latter half of the 19th century, the U.S. oil industry was born in Western Pennsylvania , which supplied
9840-451: The line is under maintenance, an injury may occur as the catenary is suddenly energized. Even if the catenary is properly grounded to protect the personnel, the arc generated across the pantograph can damage the pantograph, the catenary insulator or both. Sometimes on a larger electrified railway, tramway or trolleybus system, it is necessary to power different areas of track from different power grids, without guaranteeing synchronisation of
9963-417: The majority of the state, except for the southeastern corner, has a humid continental climate ( Köppen climate classification Dfb ). The southern portion of the state has a humid subtropical climate. The largest city, Philadelphia , has a humid subtropical climate (Köppen Cfa ). Summers are generally hot and humid. Moving toward the mountainous interior of the state, the winter climate becomes colder,
10086-482: The military railway between Marienfelde and Zossen between 1901 and 1904 (length 23.4 kilometres (14.5 mi)) and an 800-metre (2,600 ft)-long section of a coal railway near Cologne between 1940 and 1949. On DC systems, bipolar overhead lines were sometimes used to avoid galvanic corrosion of metallic parts near the railway, such as on the Chemin de fer de la Mure . All systems with multiple overhead lines have
10209-409: The natural path of a wire strung between two points, a catenary curve , thus the use of "catenary" to describe this wire or sometimes the whole system. This wire is attached to the contact wire at regular intervals by vertical wires known as "droppers" or "drop wires". It is supported regularly at structures, by a pulley , link or clamp . The whole system is then subjected to mechanical tension . As
10332-442: The north-central region with York , Carlisle , and the state capital Harrisburg on the Susquehanna River in the east-central region of the state. Altoona and Johnstown are in the state's west-central region. The state's three-most populated cities, in order of size, are Philadelphia, Pittsburgh, and Allentown. As of the 2020 U.S. census , Pennsylvania had a population of 13,011,844, up from 12,702,379 in 2010. Pennsylvania
10455-627: The number of cloudy days increases, and snowfall amounts are greater. Western areas of the state, particularly locations near Lake Erie , can receive over 100 inches (250 cm) of snowfall annually, and the entire state receives plentiful precipitation throughout the year. The state may be subject to severe weather from spring through summer into autumn. Tornadoes occur annually in the state, sometimes in large numbers, such as 30 recorded tornadoes in 2011; generally speaking, these tornadoes do not cause significant damage. Cities in Pennsylvania include Philadelphia , Reading , Lebanon , and Lancaster in
10578-654: The old Dauphin County Court House until December 1821 when the Federal -style Hills Capitol, named for Lancaster architect Stephen Hills , was constructed on a hilltop land grant of four acres set aside for a seat of state government in Harrisburg by the son and namesake of John Harris, Sr. , a Yorkshire native who founded a trading post and ferry on the east shore of the Susquehanna River in 1705. The Hills Capitol burned down on February 2, 1897, during
10701-488: The other in Norristown between the main station and the Ford Street crossing. An electrified storage track is also being constructed at Miquon to allow for temporary turnback of trains at that station, as the line is periodically subjected to flooding from the Schuylkill River around Spring Mill and Conshohocken. Ongoing replacement of the line's overhead catenary , most of which is 80 years old, will continue along with
10824-402: The overhead conductor rail that runs across the entire span of the swing bridge. The gap is required for the swing bridge to be opened and closed. To connect the conductor rails together when the bridge is closed, there is another conductor rail section called "rotary overlap" that is equipped with a motor. When the bridge is fully closed, the motor of the rotary overlap is operated to turn it from
10947-483: The overhead line is limited due to the change in the height of the weights as the overhead line expands and contracts with temperature changes. This movement is proportional to the distance between anchors. Tension length has a maximum. For most 25 kV OHL equipment in the UK, the maximum tension length is 1,970 m (6,460 ft). An additional issue with AT equipment is that, if balance weights are attached to both ends,
11070-455: The pantograph as the train travels around the curve. The movement of the contact wire across the head of the pantograph is called the "sweep". The zigzagging of the overhead line is not required for trolley poles. For tramways , a contact wire without a messenger wire is used. Depot areas tend to have only a single wire and are known as "simple equipment" or "trolley wire". When overhead line systems were first conceived, good current collection
11193-457: The pantograph causes mechanical oscillations in the wire. The waves must travel faster than the train to avoid producing standing waves , which could break the wire. Tensioning the line makes waves travel faster, and also reduces sag from gravity. For medium and high speeds, the wires are generally tensioned by weights or occasionally by hydraulic tensioners. Either method is known as "auto-tensioning" (AT) or "constant tension" and ensures that
11316-411: The pantograph moves along under the contact wire, the carbon insert on top of the pantograph becomes worn with time. On straight track, the contact wire is zigzagged slightly to the left and right of the centre from each support to the next so that the insert wears evenly, thus preventing any notches. On curves, the "straight" wire between the supports causes the contact point to cross over the surface of
11439-424: The phases. Long lines may be connected to the country's national grid at various points and different phases. (Sometimes the sections are powered with different voltages or frequencies.) The grids may be synchronised on a normal basis, but events may interrupt synchronisation. This is not a problem for DC systems. AC systems have a particular safety implication in that the railway electrification system would act as
11562-519: The reactive upward pull of the tensioned wires lift the pulley so its teeth are well clear of a stop on the mast. The pulley can turn freely while the weights move up or down as the wires contract or expand. If tension is lost the pulley falls back toward the mast, and one of its teeth jams against the stop. This stops further rotation, limits the damage, and keeps the undamaged part of the wire intact until it can be repaired. Other systems use various braking mechanisms, usually with multiple smaller pulleys in
11685-429: The remainder from Africa (5%), North America (3.1%), and Oceania (0.4%). The state's largest ancestry groups, expressed as a percentage of total people who responded with a particular ancestry for the 2010 census, were German 28.5%, Irish 18.2%, Italian 12.8%, African Americans 9.6%, English 8.5%, Polish 7.2%, and French 4.2%. As of 2018, the top countries of origin for Pennsylvania's immigrants were India ,
11808-510: The signal replacement. Also occurring in conjunction with these projects are the replacement of crossties , renewal of grade crossing surfaces, and trimming of brush and trees alongside the right-of-way. SEPTA activated PTC on the Norristown Branch on August 15, 2016. Pennsylvania This is an accepted version of this page Pennsylvania ( / ˌ p ɛ n s ɪ l ˈ v eɪ n i ə / PEN -sil- VAY -nee-ə , lit. ' Penn's forest country ' ), officially
11931-466: The southeast, Pittsburgh in the southwest, and the tri-cities of Allentown , Bethlehem , and Easton in the central east, known as the Lehigh Valley . The northeast includes the former anthracite coal mining cities of Scranton , Wilkes-Barre , Pittston , Nanticoke , and Hazleton . Erie is located in the northwest. State College is located in the central region. Williamsport is in
12054-581: The state to fill low-skill jobs in agriculture and service industries. For example, in Chester County , Mexican immigrants brought the Spanish language , increased Catholicism , high birth rates, and cuisine when they were hired as agricultural laborers; in some rural localities, they made up half or more of the population. Stateside Puerto Ricans built a large community in the state's third-largest city, Allentown , where they comprise over 40% of
12177-827: The state. In 1923, President Calvin Coolidge established the Allegheny National Forest under the authority of the Weeks Act of 1911. The forest is located in the northwest part of the state in Elk , Forest , McKean , and Warren Counties for the purposes of timber production and watershed protection in the Allegheny River basin. The Allegheny is the state's only national forest. Pennsylvania manufactured 6.6 percent of total U.S. military armaments produced during World War II , ranking sixth among
12300-601: The state." The ensuing hostilities became known as Pontiac's War . After the Stamp Act Congress of 1765, delegate John Dickinson of Philadelphia wrote the Declaration of Rights and Grievances . The Congress was the first meeting of the Thirteen Colonies , which convened at the request of the Massachusetts assembly; nine of the 13 colonies sent delegates. Dickinson then wrote Letters from
12423-420: The stiffness of the spring for ease of maintenance. For low speeds and in tunnels where temperatures are constant, fixed termination (FT) equipment may be used, with the wires terminated directly on structures at each end of the overhead line. The tension is generally about 10 kN (2,200 lbf). This type of equipment sags in hot conditions and is taut in cold conditions. With AT, the continuous length of
12546-488: The strands. All 19 strands could be made of the same metal or a mix of metals based on the required properties. For example, steel wires were used for strength, while aluminium or copper wires were used for conductivity. Another type looked like it had all copper wires but inside each wire was a steel core for strength. The steel strands were galvanized but for better corrosion protection they could be coated with an anti-corrosion substance. In Slovenia , where 3 kV system
12669-514: The tension is virtually independent of temperature. Tensions are typically between 9 and 20 kN (2,000 and 4,500 lbf ) per wire. Where weights are used, they slide up and down on a rod or tube attached to the mast, to prevent them from swaying. Recently, spring tensioners have started to be used. These devices contain a torsional spring with a cam arrangement to ensure a constant applied tension (instead of varying proportionally with extension). Some devices also include mechanisms for adjusting
12792-549: The town. All 40 civilians and 4 Al-Qaeda hijackers on board were killed. The hijackers had intended to crash the plane into either the United States Capitol or The White House . After learning from family members via air phone of the earlier attacks on the World Trade Center , however, Flight 93's passengers revolted against the hijackers and fought for control of the plane, causing it to crash. It
12915-494: The train or tram and back to the feeder station through the steel wheels on one or both running rails. Non-electric locomotives (such as diesels ) may pass along these tracks without affecting the overhead line, although there may be difficulties with overhead clearance . Alternative electrical power transmission schemes for trains include third rail , ground-level power supply , batteries and electromagnetic induction . Vehicles like buses that have rubber tyres cannot provide
13038-470: The tram wire. The tram's pantograph bridges the gap between the different conductors, providing it with a continuous pickup. Where the tram wire crosses, the trolleybus wires are protected by an inverted trough of insulating material extending 20 or 30 mm (0.79 or 1.18 in) below. Until 1946, a level crossing in Stockholm , Sweden connected the railway south of Stockholm Central Station and
13161-444: The trolleybus wires must be insulated from tram wires. This is usually done by the trolleybus wires running continuously through the crossing, with the tram conductors a few centimetres lower. Close to the junction on each side, the tram wire turns into a solid bar running parallel to the trolleybus wires for about half a metre. Another bar similarly angled at its ends is hung between the trolleybus wires, electrically connected above to
13284-533: The unification of the states. Established in 1773, it was ratified on September 9, 1783, five days after the Treaty of Paris . James Smith wrote that in 1763, "the Indians again commenced hostilities, and were busily engaged in killing and scalping the frontier inhabitants in various parts of Pennsylvania. This state was then a Quaker government, and at the first of this war the frontiers received no assistance from
13407-406: The upper lobe of the contact wire. These grooves vary in number and location on the arc of the upper section. Copper is chosen for its excellent conductivity, with other metals added to increase tensile strength. The choice of material is chosen based on the needs of the particular system, balancing the need for conductivity and tensile strength. Catenary wires are kept in mechanical tension because
13530-516: The vast majority of kerosene for years thereafter. As the Pennsylvania oil rush developed, Pennsylvania's oil boom towns, such as Titusville , rose and later fell. Coal mining, primarily in the state's Coal Region in the northeast region of the state, also was a major industry for much of the 19th and 20th centuries. In 1903, Milton S. Hershey began construction on a chocolate factory in Hershey, Pennsylvania ; The Hershey Company grew to become
13653-499: The whole tension length is free to move along the track. To avoid this a midpoint anchor (MPA), close to the centre of the tension length, restricts movement of the messenger/catenary wire by anchoring it; the contact wire and its suspension hangers can move only within the constraints of the MPA. MPAs are sometimes fixed to low bridges, or otherwise anchored to vertical catenary poles or portal catenary supports. A tension length can be seen as
13776-550: Was eventually adopted, and the coal and iron police were banned. At the beginning of the 20th century, Pennsylvania's economy centered on steel production, logging , coal mining , textile production, and other forms of industrial manufacturing . A surge in immigration to the U.S. during the late 19th and early 20th centuries provided a steady flow of cheap labor for these industries, which often employed children and people who could not speak English from Southern and Eastern Europe . Thousands of Pennsylvanians volunteered during
13899-727: Was known for its relatively peaceful relations with native tribes, innovative government system , and religious pluralism . Pennsylvania played a vital and historic role in the American Revolution and the ultimately successful quest for independence from the British Empire , hosting the First and Second Continental Congress in Philadelphia , which formed the Continental Army and appointed George Washington as its commander in 1775, and unanimously adopted
14022-765: Was not yet in British possession, but the sale boxed in the portion of New Netherland on the West side of the Delaware River. The British conquest of New Netherland began on August 29, 1664, when New Amsterdam was coerced to surrender while facing cannons on British ships in New York Harbor . The conquest was completed in October 1664, when the British captured Fort Casimir in what today is New Castle, Delaware . The Treaty of Breda between England, France, and
14145-543: Was once again chosen to be cradle to the new nation. The Constitution was drafted and signed at the Pennsylvania State House in Philadelphia, now known as Independence Hall , the same building where the Declaration of Independence was previously adopted and signed in 1776. On December 12, 1787, Pennsylvania was the second state to ratify the U.S. Constitution , five days after Delaware became
14268-674: Was originally devised by the Pennsylvania Railroad and was continued by Amtrak and adopted by Metro North . Metal signs were hung from the catenary supports with the letters "PB" created by a pattern of drilled holes. A special category of phase break was developed in America, primarily by the Pennsylvania Railroad. Since its traction power network was centrally supplied and only segmented by abnormal conditions, normal phase breaks were generally not active. Phase breaks that were always activated were known as "Dead Sections": they were often used to separate power systems (for example,
14391-556: Was partially reversed on February 9, 1674, when the Treaty of Westminster ended the Third Anglo-Dutch War and reverted all political situations to the status quo ante bellum . The British retained the Dutch Counties with their Dutch names. By June 11, 1674, New York reasserted control over the outlying colonies, including Upland, and the names started to be changed to British names by November 11, 1674. Upland
14514-439: Was partitioned on November 12, 1674, producing the general outline of the current border between Pennsylvania and Delaware. On February 28, 1681, Charles II granted a land charter to Quaker leader William Penn to repay a debt of £16,000 (around £2,100,000 in 2008, adjusting for retail inflation) owed to William's father. The transaction represents one of the largest land grants to an individual in history. Penn proposed that
14637-429: Was possible only at low speeds, using a single wire. To enable higher speeds, two additional types of equipment were developed: Earlier dropper wires provided physical support of the contact wire without joining the catenary and contact wires electrically. Modern systems use current-carrying droppers, eliminating the need for separate wires. The present transmission system originated about 100 years ago. A simpler system
14760-488: Was proposed in the 1970s by the Pirelli Construction Company, consisting of a single wire embedded at each support for 2.5 metres (8 ft 2 in) of its length in a clipped, extruded aluminum beam with the wire contact face exposed. A somewhat higher tension than used before clipping the beam yielded a deflected profile for the wire that could be easily handled at 400 km/h (250 mph) by
14883-441: Was the most significant nuclear accident in U.S. commercial nuclear power plant history. The state was hard-hit by the decline and restructuring of the steel industry and other heavy industries during the late 20th century. With job losses came heavy population losses, especially in the state's largest cities. Pittsburgh lost its place among the top ten most populous cities in the United States by 1950, and Philadelphia dropped to
15006-657: Was the only one of the four aircraft hijacked that day that never reached its intended target and the heroism of the passengers has been commemorated. Since 2003, the Tekko anime convention has been held annually in Pittsburgh. In October 2018, the Tree of Life – Or L'Simcha Congregation , a conservative Jewish synagogue, experienced the Pittsburgh synagogue shooting , which resulted in 11 fatalities. On July 13, 2024, near Butler, Pennsylvania , an assassination attempt on
15129-468: Was used, with the brass contact running inside the groove. When the overhead line was raised in the Simplon Tunnel to accommodate taller rolling stock, a rail was used. A rigid overhead rail may also be used in places where tensioning the wires is impractical, for example on moveable bridges . In modern uses, it is very common for underground sections of trams, metros, and mainline railways to use
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