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.

Box Tunnel, Great Western Railway, Wiltshire

Isambard Kingdom Brunel’s Box Tunnel is celebrated for its engineering significance – and for its entertaining legends.

Driven through the unfriendly Cotswold geology, at the time of construction it was, at 3,212 yards, the longest railway tunnel in the world, though several earlier canal tunnels were longer.

Furthermore, Brunel designed it on a gradient of 1 in 100, descending from east to west.  Contemporary critics warned against “the concussion of the atmosphere and the vibration” arising from trains labouring up the grade, and predicted a downhill runaway would leave the tunnel at a speed of 120mph, a calculation which failed to account for friction and air-resistance:  Brunel’s more realistic computation arrived at a speed of 56mph.

The tunnel was ready for the first train to run from London to Bristol on June 30th 1841.  The west portal, visible from the main road through the village of Box, is an elaborate classical composition.  Its arch is far taller than necessary, and the rock-hewn bore funnels to the conventional loading-gauge within.  The plainer east portal at Corsham lies in a cutting.

One of the enduring stories about Box Tunnel is that Brunel aligned it so that the sunrise would shine through the dead-straight bore on the morning of his birthday, April 9th.  This is within the range of practical possibility, apparently, but difficult in the circumstances to check.

The underground Bath stone quarries which lie under Box Hill to the north of Brunel’s railway tunnel have excited considerable speculation.

Ridge Quarry was used as an ammunition store in the First World War until 1922, and became Central Ammunition Depot Corsham in 1934-6.  It was used by the RAF until 1955 and then by the Army until 1964.

A much larger complex comprising some 2¼ million square feet of storage space, based on the former Eastlays, Monkton Farleigh and Tunnel Quarries, was adapted in the 1930s as a huge subterranean ammunition store, Central Ammunition Depot Monkton Farleigh.

This wartime facility was supplied by a narrow-gauge railway and inclines connected to a GWR siding at Shockerwick, just outside the east portal of the main-line tunnel.

In 1940 the Bristol Aircraft Company’s experimental section moved into Spring Quarry, and the Ministry of Aircraft Production built an underground aircraft-engine production plant to avoid disruption from bomb-attacks on Bristol.  Despite a reputed final cost of £20 million, the facility allegedly took four years to build, operated for eighteen months up to the end of the War and produced 523 out of a wartime total of 100,932 Bristol aircraft engines.

RAF Box, later known as RAF Rudloe Manor, was established above ground and within a subterranean area known as Brown’s Quarry to act as an important regional headquarters during and after the Second World War.

In the Cold War era part of Spring Quarry was used to build the Central Government War Headquarters, a 240-acre alternative seat for national government in the event of nuclear attack or civil disruption.  Capable of accommodating four thousand staff for up to three months, it drew its water-supply from an underground lake and was equipped with generators and temperature-control, the second largest telephone-exchange in Britain and a BBC broadcasting studio.

Peter Laurie’s early study of covert government infrastructure, Beneath the City Streets:  A Private Inquiry into the Nuclear Preoccupations of Government (Allen Lane 1970;  revised Panther 1979), pointed out that trains running through Box Tunnel audibly traversed a junction, which – he speculated – would allow trains, including the Royal Train from Slough, to disappear into the safety of an underground citadel.

The actual evacuation procedure apparently involved concentrating staff at Kensington (Olympia) station and transporting them by rail via North Pole Junction and Westbury to Warminster, from where they would be conveyed by road to Corsham.

The Prime Minister and his immediate entourage would be the last to arrive, by helicopter directly to Corsham.

The headquarters was apparently abandoned in 2004.

A further facility, the Corsham Computer Centre was established in the former Hudswell Quarry in the 1980s, and remains part of the Bristol Bath Total Facilities Management Project:  http://www.indymedia.org.uk/en/2003/11/280247.html.

According to internet sources which may not be up to date, Eastlays Quarry is now a bonded warehouse:  http://www.nettleden.com/venues/eastlays-quarry.   Monkton Farleigh Quarry was sold in 1976 and briefly opened as a museum in 1984:  http://www.theurbanexplorer.co.uk/farleigh-down-tunnel-wiltshire.  Ridge Quarry was resold to the original owners in 1975.

In fact, the most accessible information on this former state secret is to be found on the Government website:  https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/324883/Corsham_Tunnel_version1.pdf.

The 72-page, A4 handbook for the 2012 Waterways and Railways between Thames and Severn tour, with text, photographs, maps and a reading list, is available for purchase, price £10.00 including postage and packing.  To view sample pages click here. To order a copy, please click here or, if you prefer, send a cheque, payable to Mike Higginbottom, to 63 Vivian Road, Sheffield, S5 6WJ.

Site of Savernake High Level Station, Midland & South Western Junction Railway, Wiltshire

Where the Kennet & Avon Canal enters the practically unnecessary Bruce Tunnel the towpath becomes a footpath through a tiny settlement called, Savernake after the surrounding forest.

This unlikely place used to have two railway stations, High Level and Low Level, because of the absurdities of Victorian competition.

Savernake Low Level Station, opened in 1862, was a simple junction that connected the Great Western Railway’s Berks & Hants line with the nearby town of Marlborough, where the terminus station was called, perversely, High Level.

The other railway that served this isolated spot was the Midland & South Western Junction Railway which ran a tortuous route between Cheltenham Spa and Southampton.  A small section of this line is preserved as the Swindon & Cricklade Railway, just outside Swindon.

Built piecemeal, the M&SWJR initially opened in 1881 from Swindon to Marlborough only, linking into the GWR’s Marlborough branch and the Berks & Hants line at a rental of £1,000 per annum.

Eventually, the last piece of the jigsaw that was the M&SWJR was a nominally independent line, the Marlborough & Grafton Railway, opened in 1898, which provided an independent link from Marlborough Low Level Station to Savernake, where the station was called High Level, and joining end-on to the existing M&SWJR line at Grafton.

From early in 1892 the insolvent M&SWJR was managed by Sam Fay, who retrieved it from the receivers while on secondment from the L&SWR.  He became L&SWR line superintendent in 1899 before moving on to national fame as General Manager of the Great Central Railway in 1902

In the early years, milk was the main freight commodity at most M&SWJR stations;  other distinctive traffics were pigeons and racehorses.

At the 1922 amalgamation of railway companies, both these lines became part of the Great Western Railway which continued to operate them side by side until 1933.

In that year the GWR closed its branch and station to passengers, though retaining the track for freight, and concentrated passenger service at Marlborough Low Level.  Curiously, the two tracks were then worked as parallel single lines – the former up (towards Swindon) line as a branch between Savernake and Marlborough, the former down (towards Grafton) as a bidirectional through route.

Despite extremely heavy military traffic during the Second World War, traffic drained away in the post-war period.  British Railways continued to operate the Marlborough branch service after a landslip in 1958 by diverting trains back on to the former GWR alignment into Savernake Low Level Station, until the entire M&SWJR closed to traffic on September 10th 1961.

Half a century after the branch trains stopped running to Marlborough there is very little evidence of the two branch lines, except by viewing satellite images.  The two Marlborough station sites have been redeveloped and the M&SWJR tunnel has been filled in.

At Savernake, main-line trains still speed along the Berks & Hants line on their way between Reading and Taunton, but the site of Savernake Low Level Station has been obliterated.  The main building at Savernake High Level Station and the adjacent signal box still stand, converted to a private residence.

With heavy irony, what might have been the stationmaster’s house at Savernake Low Level is now called Beeching Villa.

All the railway sites at Savernake are on private land but are visible from the road.

The 72-page, A4 handbook for the 2012 Waterways and Railways between Thames and Severn tour, with text, photographs, maps and a reading list, is available for purchase, price £10.00 including postage and packing.  To view sample pages click here. To order a copy, please click here or, if you prefer, send a cheque, payable to Mike Higginbottom, to 63 Vivian Road, Sheffield, S5 6WJ.

Bruce Tunnel, Kennet & Avon Canal, Wiltshire: west portal

Just as the proprietors of the Kennet & Avon Canal named the Dundas Aqueduct at Limpley Stoke after the company chairman, Charles Dundas, 1st Baron Amesbury, so they named the tunnel at Savernake after the local landowner Thomas Brudenell-Bruce, 1st Earl of Ailesbury (1729-1814).

Bruce Tunnel wasn’t in fact needed.  It was built solely because the Earl declined to have a deep cutting splitting his estate.

It’s 502 yards long, with a wide bore to take Newbury barges, and has no towpath.

Above the west entrance portal is a stone panel carved with an elaborate dedication by Benjamin Lloyd, the canal company’s mason:

The Kennet and Avon Canal Company
Inscribe this TUNNEL with the Name of
BRUCE
In Testimony of the Gratitude
for the uniform and effectual Support of
The Right honourable THOMAS BRUCE EARL of AILESBURY
and CHARLES LORD BRUCE his Son
through the whole Progress of this great National Work
by which a direct communication by Water was opened

between the cities of LONDON and BRISTOL

ANNO DOMINI 1810

The inscription is almost illegible, so a modern duplicate, smaller and in a different stone, stands to the side of the tunnel arch, with a pendant:

“This monument was erected by the Kennet & Avon Canal Partnership and John Lloyd, seventh generation mason of Bedwyn, as a replica of that erected by his ancestor, Benjamin Lloyd, mason of Bedwyn to the Kennet & Avon Canal Company, AD 2003.”

John Lloyd delivered the new inscriptions, appropriately, by boat.

The 72-page, A4 handbook for the 2012 Waterways and Railways between Thames and Severn tour, with text, photographs, maps and a reading list, is available for purchase, price £10.00 including postage and packing.  To view sample pages click here. To order a copy, please click here or, if you prefer, send a cheque, payable to Mike Higginbottom, to 63 Vivian Road, Sheffield, S5 6WJ.

Sapperton Tunnel, Thames & Severn Canal, Gloucestershire: Coates Portal

Sapperton Tunnel on the Thames & Severn Canal epitomises the canal-builder’s dilemma about crossing a watershed – whether to dig an expensive tunnel to save lockage, or to build locks that demand a constant and abundant source of water.

Sapperton Tunnel cost a great deal to build, and leaked like a sieve.

The engineer Josiah Clowes is thought to have worked on the 2,880-yard, nine-foot-wide Harecastle Tunnel on the Trent & Mersey Canal for James Brindley, and Sapperton Tunnel was longer, at 3,817 yards, and was built to broad-canal dimensions without a towpath.  At the time of construction it was the longest tunnel so far built.

Work began in the spring of 1784 and was completed in 1789:  the first boat went through on April 20th that year.  Defects in the structure led to a ten-week closure only a year after the opening.

The original surveyor of the Thames & Severn Canal, Robert Whitworth, had observed, on a frankly superficial inspection, that the summit level ran “over some bad Rocky Ground…worse than [he had] even seen any Canal cut thro’ for such a continued length”.

In fact, the line of the tunnel alternately passes through impermeable oolite and the unstable, permeable clay known as fuller’s earth:  http://www.cotswoldcanals.com/pages/locks-bridges-structures/sapperton-tunnel.php.

The geologist John Phillips (1800-1874), in his biography of his geologist uncle Memoirs of William Smith (1844), wrote scathingly about the fundamental weakness of the line:

Such canals…are like the buckets of the Danaids, and with the water goes the profit.  In vain the Thames, raised from its source by a mighty engine, is poured into such a thirsty canal;  the flood passes into the gaping rocks below, in spite of renewed puddling and continual repairs.

The last boat went through Sapperton Tunnel on May 11th 1911 and almost the entire canal was abandoned in 1927.

The Cotswolds Canal Trust has been working since 1975 to restore the entire length of the Thames & Severn Canal, and the reopening of Sapperton Tunnel forms part of the third and final phase of their project:  http://www.cotswoldcanals.net/tunnel.php.

It won’t be easy, as Ken Burgin’s inspection 2009 report indicates:  http://www.cotswoldcanals.net/downloads/CCT_Tunnel_Report_Trow_Spring_2009.pdf.

The 72-page, A4 handbook for the 2012 Waterways and Railways between Thames and Severn tour, with text, photographs, maps and a reading list, is available for purchase, price £10.00 including postage and packing.  To view sample pages click here. To order a copy, please click here or, if you prefer, send a cheque, payable to Mike Higginbottom, to 63 Vivian Road, Sheffield, S5 6WJ.

Clifton Suspension Bridge, Bristol

The first high-level crossing of the Avon Gorge at Bristol was not, in fact, Isambard Kingdom Brunel’s suspension bridge, but a wrought-iron bar, installed in 1836 when bridge-building was about to begin, a thousand feet long and 1½ inches thick, suspended two hundred feet above the River Avon, to carry a basket for transporting materials hung from a roller.

Brunel made the first trip across (after his newly-wed wife, Mary Elizabeth Horsley, declined the opportunity) and got stuck halfway when the bar dipped.  He shinned up the suspension ropes to free the pulley and reached the opposite bank without further difficulty.

By 1843, with £45,500 spent, only the piers had been completed, linked by the single iron bar:  work stopped – to Brunel’s lifelong disappointment – and the unused suspension chains were sold and incorporated in his railway bridge across the Tamar at Saltash.

L T C Rolt, in his biography Isambard Kingdom Brunel (1957;  revised edition with an introduction by Angus Buchanan 1990), reports that when construction of the bridge stopped for lack of funds, the Clifton Bridge Company collected £125 in fares from members of the public who wished to ride across in the bucket.

The bridge as we know it was completed, to a variant of Brunel’s original design, in 1864 using the chains from another of his suspension bridges, across the River Thames at Hungerford.

The 72-page, A4 handbook for the 2012 Waterways and Railways between Thames and Severn tour, with text, photographs, maps and a reading list, is available for purchase, price £10.00 including postage and packing.  To view sample pages click here. To order a copy, please click here or, if you prefer, send a cheque, payable to Mike Higginbottom, to 63 Vivian Road, Sheffield, S5 6WJ.