The Wharncliffe Viaduct is a brick-built viaduct that carries the railway across the Brent Valley, between Hanwell and Southall, Ealing, at an elevation of 65 feet.
The viaduct, built in 1836-7, was constructed for the opening of the Great Western Railway (GWR) and was the first major structural design by Isambard Kingdom Brunel.
Constructed of engineering brick, this 900-foot-long Georgian viaduct has eight semi-elliptical arches, each spanning 70 feet and rising 17 feet 6 inches. It is 55 feet wide. The supporting piers are hollow and tapered, rising to projecting stone cornices that held up the arch centring during construction.
When built, the viaduct was designed to carry two broad gauge tracks: the piers were 30 feet wide at ground level and 33 feet wide at deck level.
The contractor was the partnership of Thomas Grissell and Samuel Morton Peto and the cost was £40,000.
The Gauge Act of 1846 decreed that George Stephenson’s (narrower) standard gauge should be the standard used for all railways across the country.
In 1877 the viaduct was widened by the addition of an extra row of piers and arches on the north side.
In 1892 the broad gauge track was converted to standard gauge, and this allowed enough width for four standard gauge tracks.
On the central pier on the south side is a carving of the coat of arms of James Stuart Wortley Mackenzie, Lord Wharncliffe, who was chairman of the parliamentary committee that steered the passage of the GWR Bill through Parliament.
Brunel was quick to see the possible advantages of the early electric telegraph system for use in running the railway. In 1838 he persuaded Charles Wheatstone and William Fothergill Cooke to install their five-needle telegraph system between Paddington Station and West Drayton and to carry out experiments. It proved to be useful, so the viaduct thus carried the world’s first commercial electrical telegraph, on 9 April 1839.
At first, the seven-core cables were carried inside cast iron pipes, on short wooden spikes, a few feet from the side of the railway line. But from January 1843, the public were treated to the sight of telegraph wires against the sky line, across the top of the viaduct, for the first time. Cooke had renegotiated the contract with the GWR and extended the telegraph to Slough, using a simpler two-needle instrument that could be supplied with just two wires suspended from porcelain insulators on poles.
On 16 May 1843 the Paddington-to-Slough telegraph went public, becoming Britain’s first public telegraph service. Despite being something of a publicity stunt for Cooke, it became very popular, and HM Government were frequently using it for communication with the royal household at Windsor Castle nearby.
The Wharncliffe Viaduct is best viewed from Brent Meadow on the south side, accessed from the Uxbridge Road, opposite Ealing Hospital. This is an area being maintained as a traditional hay meadow and is part of the Brent River Park.