Chester Road Swing Bridge.

The bridge carries the busy A56 trunk road across the canal at Warrington and  is constructed so that it rests on an annular girder some 31 feet in diameter, supported by a   pivot and a roller path.  Sunk into the concrete  base  is a lower roller containing  between 60 and 64 individual cast iron rollers. A toothed rack is bolted to the annular girder and is set in motion by hydraulic pinions whenever the bridge is swung.   Gates on the roadway control the road traffic when the bridge is being swung.