The Swing Bridge.

The Swing Bridge is over the River Tyne, connecting Newcastle Upon Tyne and Gateshead,and lies between the Tyne Bridge and the High Level Bridge.
The mechanism used for this is still the same machinery originally installed by William Armstrong.
The hydraulic Swing Bridge, was designed and paid for by William Armstrong to enable larger ships to move upstream to his works.
It was first used for road and river traffic in 1876.
The Swing Bridge stands on the site of the Old Tyne Bridges of 1270 and 1781, and probably of the Roman Pons Aelius.