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Moy Swing Bridge, Caledonian Canal
Caledonian Canal near Gairlochy, Highland
Moy Swing Bridge, Caledonian Canal
associated engineer
Thomas Telford
William Jessop
date  1820
UK era  Georgian  |  category  Bridge  |  reference  NN161826
ICE reference number  HEW 84/05
photo  © and licensed for reuse under this
When they planned the Caledonian Canal, Thomas Telford and William Jessop decided to adopt cast iron swing bridges, or "turn-bridges", for canal crossings. Several were installed but only Moy Swing Bridge survives. It has two swinging leaves and was always operated by hand, which is still true.
The Caledonian Canal opened in 1822. It links the Irish Sea with the North Sea via Scotland's Great Glen. Thomas Telford (1757-1834) was its principal engineer, with William Jessop (1745-1814) as consulting engineer until 1812. All bridges on the canal were cast iron, except the lock-gate foorbridges. The swing bridge idea was a development of a bridge design introduced at the London and West India Docks in 1805.
Moy Swing Bridge has a single span of 12.2m and is 3m wide. Its two counter-balanced arms pivot on horizontal bearings, with their ends meeting at mid span. The original square-headed nuts and bolts can still be seen.
The ironwork was cast at Plas Kynaston in Denbighshire, Wales, at the foundry of William Hazledine (or Hazeldine, 1763-1840). He was responsible for the ironwork on the western reaches of the canal. Telford admired his skill and in 1796 called him “the Arch conjuror himself, Merlin Hazledine”. The castings were transported via Chester and the sea lock at Corpach for assembly on site.
The bridge is operated by hand. Crank handles are housed in short metal pillars, and the mechanisms are below the bridge at each side of the canal. Because each half has to be swung separately, until recently, the keeper had to row across the canal each time the bridge was operated.
The bridge was constructed without railings. White-painted iron railings were added in 1850 after the death of a contractor called Bean, who was thrown from his horse while crossing the canal.
Until refurbishment in 1995, the counter-balance weights in the back of the frame above the bearings consisted of 910mm long Jessop plate-rails, formerly used for transporting spoil during the cutting of the canal. One of these is preserved in the ICE Museum at Heriot-Watt University.
The bridge is a Scheduled Ancient Monument (No. 3447) and now part of a farm track. The single-storey bridge keeper’s cottage (NN162825) on the south side was built 1815-20 and has been a Category B listed building since June 1980.
Construction: Thomas Rhodes
Ironwork: William Hazeldine
Research: ECPK
reference sources   CEH SLBHighBrBDCE1

Moy Swing Bridge, Caledonian Canal