Newhaven Swing Bridge (1866-1976)
in Newhaven Harbour, Sussex.
This was the second of three movable bridges crossing the River Ouse in the harbour, and carried road and rail traffic. It was turned manually by a large capstan at the centre of the bridge.
For a good account of the bridge's design and construction, see here[1].
A good overview may be found here.
Photos of bridge being swung by eight men here.