page_title: Overhead line
section_title: Overhead catenary
hierarchical_section_title: Overhead line / Overhead catenary
caption_attribution_description: Brand new steam locomotive 60163 Tornado crosses the Royal Border Bridge railway viaduct in Berwick-upon-Tweed, travelling south at the head of The North Briton charter train from Edinburgh to York. This was the first time Tornado had passed over the viaduct in the southbound direction, having crossed for the first time in northbound a week earlier, hauling The Auld Reekie Express from York to Edinburgh. Tornado is brand new Peppercorn A1 class locomotive completed in 2008. The Peppercorn A1 was the last type of express passenger steam locomotive that was used on this route on the East Coast Main Line from Scotland to London. None of the original 49 survived the scrapyard in the change to diesel, and later, electric traction. Tornado is coasting at this point, the steam above the locomotive is actually coming from the boiler safety valves and not the chimney, creating a false impression of a steam exhaust. Taken at 15:12 GMT from the south bank of the River Tweed, east of the bridge, Tornado was approximately 15 minutes early for arrival in Berwick, and proceeded to Tweedmouth sidings on the other side of the bridge to take on water.
context_page_description: An overhead line or overhead wire is used to transmit electrical energy to electric trains, trolleybuses or trams. It is known variously as:
  Overhead catenary
  Overhead contact system
  Overhead equipment
  Overhead line equipment
  Overhead lines
  Overhead wiring
  Traction wire
  Trolley wire
  In this article, the generic term overhead line is used, as used by the International Union of Railways.
  An overhead line consists of one or more wires situated over rail tracks, raised to a high electrical potential by connection to feeder stations at regular intervals. The feeder stations are usually fed from a high-voltage electrical grid.
context_section_description: A catenary is a system of overhead wires used to supply electricity to a locomotive, tram (streetcar), or light rail vehicle that is equipped with a pantograph.
  Unlike simple overhead wires, in which the uninsulated wire is attached by clamps to closely spaced crosswires supported by poles, catenary systems use at least two wires. The catenary or messenger wire is hung at a specific tension between line structures, and a second wire is held in tension by the messenger wire, attached to it at frequent intervals by clamps and connecting wires known as droppers. The second wire is straight and level, parallel to the rail track, suspended over it as the roadway of a suspension bridge is over water.
  Catenary systems are suited to high-speed operations whereas simple wire systems, which are less expensive to build and maintain, are common on light rail or tram (streetcar) lines, especially on city streets. Such vehicles can be fitted with either a pantograph or trolley pole.
  The Northeast Corridor in the United States has catenary over the 600 miles (970 km) between Boston, Massachusetts and Washington, D.C. for Amtrak's inter-city trains. Commuter rail agencies including MARC, SEPTA, NJ Transit, and Metro-North Railroad utilize the catenary to provide local service.
  In Cleveland, Ohio the interurban/light rail lines and the heavy rail line use the same overhead wires, due to a city ordinance intended to limit air pollution from the large number of steam trains that passed through Cleveland between the east coast and Chicago. Trains switched from steam to electric locomotives at the Collinwood rail yards about 10 miles (16 km) east of Downtown and at Linndale on the west side. When Cleveland constructed its rapid transit (heavy rail) line between the airport, downtown, and beyond, it employed a similar catenary, using electrification equipment left over after railroads switched from steam to diesel. Light and heavy rail share trackage for about 3 miles (4.8 km) along the Cleveland Hopkins International Airport Red (heavy rail) line, Blue and Green interurban/light rail lines between Cleveland Union Terminal and just past East 55th Street station, where the lines separate.
  Part of the Boston, Massachusetts Blue Line through the northeast suburbs uses overhead lines, as does the Green Line.
caption: An older rail bridge in Berwick-upon-Tweed, retrofitted to include overhead catenary lines
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