The Liverpool & Manchester line had to cross the trench-like valley of the Sankey Brook. The Sankey Brook Navigation Company objected to the building of the railway and made life difficult for George Stephenson and his team of engineers by insisting on a 60 ft clearance over their canal. William Allcard was given the responsibility of designing the Sankey Viaduct and came up with a nine arch structure. Each of the arches is of 50 ft span and rises from massive sandstone slabs quarried locally, including at Olive Mount. Thousands of tons of marl and moss, compacted with brushwood, was used to increase the height of the embankment. The Sankey Viaduct was built of brick with stone facings and cost the company over £45,000 to produce.