While Isambard Kingdom Brunel’s pioneering Wharncliffe Viaduct was under construction in the early stages of building the Great Western Railway from 1836, he was simultaneously engaged on a more audacious project, the Maidenhead Viaduct, where the line needed to cross the River Thames.

The Thames Navigation Commissioners were adamant that the river channel and both towpaths must not be obstructed, yet Brunel was determined to restrict the ruling gradient of the railway to 1 in 1,320 (0.076%). 

He located the crossing to take advantage of a midstream island, Bucks Ait, that could accommodate a bridge pier, and designed two brickwork spans, each 128 feet long, that rose only 24 feet in height.  The arches remain the flattest brick spans ever constructed.

The GWR directors lacked Brunel’s confidence in his design, especially after the contractor, William Chadwick, lowered the centring before the mortar had fully set, and the lower courses of the eastern arch dropped half an inch. 

Chadwick took responsibility and reinstated the brickwork, but Brunel was ordered to leave the centring in place when trains began to cross the bridge in July 1839.

His response was to quietly lower the timberwork a few inches, so that arches were self-supporting, while insisting that they remain in situ over the coming winter.  Brunel’s biographer, L T C Rolt, wryly observes, “The suspicion that this was due not so much to excessive caution as to an impish sense of humour is hard to resist.”

Indeed, when an autumn storm destroyed the centring and the bridge remained firm, Brunel’s critics were silenced.

The artist J M W Turner depicted the Maidenhead Viaduct in his painting ‘Rain, Steam and Speed’ (1844), the first time a railway train had been portrayed in a sophisticated work of art.

The Maidenhead Viaduct remains almost exactly as it was built, except that it was widened in 1877 by Sir John Fowler, who took great trouble to preserve the proportions of Brunel’s design, though he used darker Cattybrook brick from Gloucestershire.  When the broad-gauge tracks were removed in 1892 the line was quadrupled. 

Similar care to preserve the beauty of Brunel’s engineering was taken when the line was electrified in 2017.

Oddly, when the viaduct was listed in 1950 only the western arch was designated Grade II*;  the eastern arch was added to the designation in 1985.  The entire bridge was upgraded to Grade I in 2012.

The name “The Sounding Arch” arose because of the spectacular echo.  If you stand underneath the arch on the Taplow towpath and clap, you may be rewarded with six or more echoes.  People on TripAdvisor complain that there isn’t an echo.  People complaining on TripAdvisor is not uncommon.

The rail journey from Paddington to Bristol tells the story of the start of Isambard Kingdom Brunel’s spectacular career as a civil engineer.  He was thirty when construction of the Great Western Railway began in 1836, and he barely stopped working until he died, worn out, at fifty-three in 1859.

The first major structure out of Paddington, the Wharncliffe Viaduct, carries trains 66 feet above the valley of the River Brent on eight graceful arches.

Otherwise known as the Hanwell Viaduct, it’s named as a compliment to James Stuart-Wortley, 1st Baron Wharncliffe (1776-1845), who chaired the parliamentary committee that considered and approved the passage of the Great Western Railway Act (1835).  His lordship’s coat of arms embellishes the south face of the viaduct.

Opened in 1838, it’s not the first major railway viaduct – George Stephenson’s Sankey Viaduct in Lancashire dates from 1830 – but it can claim a fistful of other firsts.

It was Brunel’s first major civil-engineering project, yet with audacious confidence he designed it as the first bridge in the world to have hollow piers, saving cost without sacrificing structural strength. 

The interiors of the piers are a favourite roost for colonies of bats, whose privacy is carefully safeguarded by naturalists.

Brunel saw the potential of Sir Charles Wheatstone and William Fothergill Cooke’s new electric telegraph, and persuaded them to lay down experimental telegraph cables alongside the track.  The system proved practical in 1839, making Hanwell the first viaduct in the world to carry a commercial telegraph.  The system was opened to the public in 1843.

This proved invaluable when a suspected murderer, John Tawell, was identified as he boarded a train at Slough and a telegraph message, describing him as “a Kwaker [sic] with a brown great coat on which reaches his feet” and locating his first-class compartment, was passed to Paddington station.  He was duly arrested when he alighted on New Year’s Day 1845.

Queen Victoria travelled by train for the first time from Windsor to London on June 13th 1842, and on at least one occasion is said to have ordered a stop on the viaduct so she could admire the view.

Brunel designed it to carry two broad-gauge tracks, and in 1877 a duplicate set of arches were added to the north side to carry a third line.  The abolition of the broad gauge in 1892 enabled the viaduct to carry four standard-gauge tracks. 

The viaduct continues to prove useful as technology develops.  It now carries transatlantic telephone and latterly fibre-optic cables and overhead power-lines to propel electric trains.

It became one of the first structures in Britain to be listed as a building of architectural and historic importance in 1949, and was commended by Sir Nikolaus Pevsner in The Buildings of England for its “architectural panache”:  its tapered piers are capped by stone cornices that carried the timber centering that supported the arches during construction.

The Wharncliffe Viaduct is easily accessible from Hanwell station, which is now served solely by the Elizabeth Line.  On arrival from London turn right out of the station and head towards the A4060 Uxbridge Road.  Continue away from London to Brent Meadow, an open space beside the Viaduct pub, which until Brunel came along was the eighteenth-century Coach & Horses.  Footpaths lead directly to the viaduct.