Constructed of brick, the 900ft long bridge has 8 arches, each spanning 70ft and rising 17ft 6ins. The supporting piers are hollow and tapered, rising to projecting stone cornices that held up the arch centring during construction.

Originally, the piers were 30ft wide at ground level and 33ft at deck level. The deck was designed to accommodate two tracks of Brunel's broad gauge railway.

However, an Act of Parliament was passed in 1846 that made Stephenson's narrow gauge standard across the country and so the viaduct was widened in 1847 by the addition of an extra row of piers and arches on the north side. The new width is 55ft.

The viaduct is still used today for trains running from Paddington to Bristol. Lord Wharncliffe's coat of arms can been seen on the central pier on the south side. He was chairman of the Great Western Railway.

Original contractor: Grissell & Peto