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The Swing Bridge is a swing bridge over the River Tyne, England, connecting Newcastle upon Tyne and Gateshead, and lies between the Tyne Bridge and the High Level Bridge. The machine room, showing one of Armstrong's original three-cylinder oscillating hydraulic motors The hydraulic power still used to move the bridge is today derived from electrically driven pumps. These feed a hydraulic accumulator sunk into a 60 foot (18 m) shaft below the bridge; the water is then released under pressure which runs the machinery to turn the bridge. The mechanism used for this is still the same machinery originally installed by Armstrong. It has an 281 feet (85.6 m) cantilevered span with a central axis of rotation able to move through 360 to allow vessels to pass on either side of it. The previous bridge on the site was demolished in 1868 to enable larger ships to move upstream to William Armstrong's works.The hydraulic Swing Bridge was designed and paid for by Armstrong, with work beginning in 1873. It was first used for road traffic on 15 June 1876 and opened for river traffic on 17 July 1876.At the time of construction it was the largest swing bridge ever built. The construction costs were �240,000. The Swing Bridge stands on the site of the Old Tyne Bridges of 1270 and 1781, and probably of the Roman Pons Aelius....R.