When the Bridgewater Canal was first built, there was the problem of how to get the line over the Irwell valley. James Brindley overcame this in 1761 with an aqueduct, which was cutting edge at the time. When, in the 1890's, the Manchester Ship Canal was being constructed, they found that the ships were too tall to go under the aqueduct. Sir Edward Leader Williams (engineer to the Manchester Ship Canal Company) came up with the idea to construct a rotating aqueduct as a replacement. It opened to commercial traffic in 1894. Originally steam-powered, it is now driven by electricity.