page_title: Overhead line
section_title: Gaps
hierarchical_section_title: Overhead line / Breaks / Gaps
caption_attribution_description: Nederlands: Roterende spoorbrug bij Meppel Čeština: Otočný železniční most u Meppelu
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: 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 a cheaper 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.
caption: A swing bridge near Meppel, the Netherlands. There is no overhead line on the bridge; the train coasts through with raised pantograph.
exif: {"Image Make": "Canon", "Image Model": "Canon EOS 450D", "Image Orientation": "Horizontal (normal)", "Image XResolution": "72", "Image YResolution": "72", "Image ResolutionUnit": "Pixels/Inch", "Image DateTime": "2009:09:19 13:40:42", "Image YCbCrPositioning": "Co-sited", "Image ExifOffset": "196", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "9648", "Thumbnail JPEGInterchangeFormatLength": "7866", "EXIF ExposureTime": "1/200", "EXIF FNumber": "10", "EXIF ExposureProgram": "Program Normal", "EXIF ISOSpeedRatings": "200", "EXIF ExifVersion": "0221", "EXIF DateTimeOriginal": "2009:09:19 13:40:42", "EXIF DateTimeDigitized": "2009:09:19 13:40:42", "EXIF ComponentsConfiguration": "YCbCr", "EXIF ShutterSpeedValue": "61/8", "EXIF ApertureValue": "53/8", "EXIF ExposureBiasValue": "0", "EXIF MeteringMode": "Pattern", "EXIF Flash": "Flash did not fire, compulsory flash mode", "EXIF FocalLength": "40", "EXIF SubSecTime": "43", "EXIF SubSecTimeOriginal": "43", "EXIF SubSecTimeDigitized": "43", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "4272", "EXIF ExifImageLength": "2848", "Interoperability InteroperabilityIndex": "R98", "Interoperability InteroperabilityVersion": "[48, 49, 48, 48]", "EXIF InteroperabilityOffset": "9506", "EXIF FocalPlaneXResolution": "2136000/439", "EXIF FocalPlaneYResolution": "356000/73", "EXIF FocalPlaneResolutionUnit": "2", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Auto", "EXIF SceneCaptureType": "Standard"}