Cast iron has been around for centuries but it was only during the Industrial Revolution, in Britain, that it began to be produced cheaply enough and in sufficient quantities to be used for a wide range of purposes.
From the late 18th Century onwards, cast iron and canals go together. Telford’s pioneering iron trough aqueduct at Longdon-on-Tern was built in 1796 and others, notably Pontcysyllte, Cosgrove and Edstone, followed. At the same time cast iron bridges appeared, along with cast iron lock gates, cranes, mileposts, signs, boundary markers, paddle gear, bollards and all kinds of straps, anchors, fittings and other equipment.
Cast iron is strong in compression but not in tension and is vulnerable to cracking on impact. Not surprisingly, almost all the cast iron lock gates on canals like the Oxford and the Montgomery, have gone. Iron footbridges remain in many places, especially on Midlands canals. Scattered but still fairly numerous mileposts and company boundary markers that have survived the ravages of time and theft continue to delight visitors to our waterways and other examples are safely displayed in our museums.
Wooden patterns that were used for sand casting iron components were once stored in canal yards up and down the country and some of these survive too, as precious reminders of a time when cast iron was king.
National Heritage Manager
As national heritage manager, Nigel’s role is to lead the Canal & River Trust’s team of regional heritage advisers in England and Wales. He has over 25 years’ experience of working in the conservation, archaeology and interpretation of historic buildings and places. He is a member of the editorial board of the Institute of Historic Building Conservation. He has written numerous articles concerning heritage conservation and is the author of several longer published works, including the English Heritage Book of Canals.See more blogs from Nigel Crowe