Isambard Kingdom Brunel

1824–1828: Thames Tunnel

Brunel's chance to become a prominent engineer arose in July 1824, when his father was appointed as the engineer of a project to build a tunnel under the river Thames. Described by Annabel Gillings as the "most ambitious engineering project of the time", and hailed as an extreme feat in science and engineering, it was designed to alleviate the pressure on London's ferries and on its bridges, of which there were none near the London Docks. The biggest challenge was the softness of the soil below the river: a tunnel between Rotherhithe and Limehouse had been proposed by Robert Vazie in 1802, but after it collapsed inwards twice due to quicksand, the project was abandoned. The composition of the riverbed by Rotherhithe was itself little more than waterlogged sediment and loose gravel.

Marc Brunel's idea for overcoming these challenges came from the shipworm family of molluscs: their hard shell grinds and softens the wood in front of them, which they then eat and, using their faeces to fill in their own path and thus prevent the wood from collapsing. This inspired his tunnelling shield, which he patented on 20 January 1818, wherein twelve workers mined from within a huge cast-iron shield and the spoil was converted to bricks behind them to form the tunnel walls. Only one person would mine at a time, and that person would only uncover, mine, and recover one of their sections at once; the shield was moved forward once this had been done for all thirty-six sections. On 19 February 1824, one day after Marc Brunel met with the Institution of Civil Engineers, the formation of the Thames Tunnel Company was announced.

The plan for the Thames Tunnel involved digging two separate bores as a dual carriageway, and to construct it very close to the riverbed to avoid the dangerous quicksand beneath. The project ceremonially began on 2 March 1825, and Brunel laid the second brick, after his father. Brunel was given the job of assistant to John Armstrong, the resident engineer of the project, a role Brunel had hoped to have himself. Due to early setbacks, the company pressured for the tunnelling to happen faster, and so the construction became more dangerous. The sewage in the Thames polluted and poisoned the workers below, and yet Brunel and his father helped to work the tunnelling shield.

In April 1826, when John Armstrong resigned due to illness, Brunel took over as resident engineer; his father then stepped down from leading the project after contracting pleurisy, with Brunel taking full charge of the engineering from 3 January 1827. At one critical point in September 1826, he refused to leave the tunnel for a total of 96 hours, which he spent working with occasional breaks to sleep. As a token of respect for the toil of the workers and their trying conditions, he moved to a cabin inside the tunnel with one of his assistants, spending his time monitoring the progress and quality of construction and ensuring the workers' discipline.

On many occasions, Brunel risked his life swimming out to rescue workers. After one such incident, he visited the workmen during their dinner and was received with applause, with their wives cutting pieces off of his coat to keep as relics. His most challenging task was dealing with the Thames Tunnel Company, which prioritised the progress of construction over workers' safety; for example, all of Marc Brunel's designs for a drain to protect the tunnel from flooding were rejected due to cost.

By April 1827, the tunnel was so close to the riverbed that discarded items were falling from the river into the tunnel, and the conditions were so polluting that one of Brunel's assistant engineers died and another was left blind in one eye. On 18 May, the river broke through into the tunnel, but luckily no one was killed, as Brunel and his assistants pulled the men out of the water. A team of engineers, including Brunel, dived into the Thames from the surface; they could see the inside of the tunnel from the river. The workers filled in the hole and drained the water, with Brunel commenting unaffected in his diaries:

I wish I had kept this journal with me even at work on the river. What a dream it now appears to me. Going down in the diving bell, finding and examining the hole, standing on the corner of No12! The novelty of the thing, the excitement by the occasional risk attending our subaquatic excursion, the crowds of boats to witness our works... what sensations!

Construction continued on 1 October; on 10 November 1827, a banquet was held in the tunnel with Brunel, his father, and the Duke of Wellington, who would become Prime Minister the next year. By 2 January 1828, water and rocks were already falling into the tunnel from the riverbed. At 6 am on 6 January, Brunel was mining using the shield along with two others when the tunnel collapsed, and Brunel's leg was caught below timber. Six miners were killed, including the two with whom Brunel had been working, but he survived with serious injuries after narrowly being pulled out of the water before he was swept away. After he woke up, he refused to leave until he had assessed the damage to the tunnel, but did not realise how much he was injured; this incident is blamed for his later frailty. He was seriously injured and spent six months recuperating in Brighton, before being sent to live with a friend in Clifton, Bristol, during which time he began a design for the Clifton Suspension Bridge over the nearby Avon Gorge.

Brunel was too ill to continue working on the tunnel and left the project, whose failure left him depressed The second collapse stopped work on the tunnel for several years, and it was bricked up in August 1828 amid ongoing negotiations on its construction. Work would not resume until 1835, and the tunnel was finished in 1843 to a different design. Brunel had no further involvement except using the abandoned works at Rotherhithe as a site for Gaz Engine-related experiments. The tunnel was only usable by pedestrians until the East London Railway Company purchased it in 1865, and four years later the first trains passed through it. Brunel's father was knighted in 1841 for his work on the tunnel, and today it is on the East London line between Rotherhithe and Wapping.

1829–1833: The Clifton Suspension Bridge

Brunel is perhaps best remembered for designs for the Clifton Suspension Bridge in Bristol, whose construction began in 1831. A competition had been announced in 1829 to design a bridge over the Avon Gorge near Bristol; at the time, crossing the gorge involved descending 250 feet (76 m) to the water, getting a ferry across, and reascending the same height, or by dangerously being sent in a basket on a zip line between the two sides. While Brunel had never designed a suspension bridge, his father helped him, and he produced four designs based on different sites for the bridge, with spans ranging from 870 feet (270 m) to the longest ever proposed at the time, at 916 feet (279 m).

Thomas Telford, the then-president of the Institution of Civil Engineers, was invited to judge the entries. The effect of the wind on his own Menai Suspension Bridge made him think Brunel's designs were too long, and he advised against them. Instead, he proposed two intermediate towers at the bottom of the gorge, splitting up the bridge. Brunel argued back that his calculations were correct and that Telford's proposed towers would sink into the ground. By 1830 it became clear that the necessary money for Telford's design could never be raised, and the competition was thus reopened.

Once again, Brunel and Telford both submitted to the second competition, with Telford simply resubmitting the same design. Brunel adapted his design to make it more favourable to the judge, Davies Gilbert, by shortening the span to 630 feet (190 m). Brunel's design was adorned with Egyptian designs, such as sphinxes and hieroglyphs, with large panels detailing the bridge's construction. Both Brunel and Telford lost to W Hawks, with Telford not even selected as a finalist; Brunel travelled to Bristol to confront Gilbert over his decision and persuaded him to change the winner. On 27 March 1831, Brunel wrote to his brother-in-law, the politician Benjamin Hawes:

Of all the wonderful feats I have performed, since I have been in this part of the world, I think yesterday I performed the most wonderful. I produced unanimity among 15 men who were all quarrelling about that most ticklish subject—taste.

On 21 July 1831, there was an opening ceremony for the construction of the bridge. However, it was quickly plagued by issues; building the approach on one side became challenging, and there was not enough money to complete the bridge. On 22 September 1831, the Reform Act passed the House of Commons, the lower elected chamber of Parliament. The bill promised radical parliamentary reform in the United Kingdom, and the House of Lords, the upper chamber whose interests the bill served against, blocked it. This led to riots that spread across the entire country, but those in Bristol were the heaviest. Brunel himself was sworn in as a "Special Constable" to help control the riots, and he hurriedly took items from Mansion House to stop them from being looted. The riots resulted in the construction of the bridge being cancelled entirely.

Brunel did not live to see the bridge finished. After his death, his colleagues and admirers at the Institution of Civil Engineers felt its completion would make a fitting memorial, and started to raise new funds. Work recommenced in 1862, three years after Brunel's death, and was completed in 1864. With a span of over 702 ft (214 m) and a nominal height of 249 ft (76 m) above the River Avon, it had the longest span of any bridge in the world at the time of construction. Brunel's biographers disagree on to what extent the final bridge reflects his winning entry. In 2011, Adrian Vaughan suggested that Brunel's final contribution was minimal; his views reflected the sentiment of Tom Rolt fifty-two years earlier in his 1959 book Brunel, and Annabel Gillings suggests that "only a fraction of [Brunel's] design is visible", and points out that his decorations were never added. However, Robert Harrison describes the bridge as "nearly in accordance with his original designs". The bridge still stands, and as of 2007, over 4 million vehicles traverse it every year.

While also working on the Clifton Suspension Bridge, Brunel also took on building the observatory of the astronomer Sir James South at his home in Kensington. On 20 May 1831, the completed observatory was opened with Brunel as a guest of honour. However, a dispute over the cost of the project escalated, and South both refused to pay and published a deeply hurtful article in The Athenaeum that called the observatory an "absurd project" and said of Brunel that it "was an effort to produce effect on the part of the architect"; Brunel considered legal action or appealing for its removal but in the end did neither. Other projects during this time included work in Bristol, where he was made engineer for their docks, and Sunderland, where he was tasked with the export of coal from the growing number of collieries, and where he designed the Monkwearmouth Docks in 1831. On 5 December 1831, he took a ride on the Liverpool and Manchester Railway (LMR); offended by its speed and constant shaking, he tried to write in his diary while the train was moving, daring them to "let me try".

Railway career

1833–1835: Beginnings of the Great Western Railway

In Autumn 1832, the first plan for a line between London and Bristol was conceived by four men in the latter city. The idea followed from the success of the LMR and the planned London and Birmingham Railway (L&BR), and picked up the support of local groups such as the Society of Merchant Venturers. While the Clifton Suspension Bridge remained incomplete during Brunel's lifetime, it had given him the opportunity to become known by the people of Bristol. When, therefore, a company was formed to build a railway to London, Brunel was floated as a possible engineer. After it was suggested that the role of Engineer would go to the person who designed the line of lowest cost, Brunel wrote to say "You are simply giving a premium to the man who makes the most flattering promises. The route I will survey will not be the cheapest – but it will be the best".

While the company did appoint Brunel as engineer in March 1833, they had him share the role with William Townsend, whose only experience was on Bristol tramways, and with whom Brunel had no interest in working. Brunel and Townsend were given ten weeks to travel the route on horseback, taking measurements and convincing landowners to sell to the company. many of whom were starkly opposed to the railway. The railway was publicised on 30 July 1833 at 116 miles (187 km), the longest ever proposed at that time. Brunel felt only one of the directors, Charles Saunders, was enthusiastic enough, and the pair became friends. The directors agreed that Brunel would be the line's engineer and confirmed the name—the Great Western Railway (GWR). He hired a team of assistants and made a mobile office out of a Britzka which contained a bed and his equipment; it soon became known as the "Flying Hearse".

On 7 September 1833, the company commissioned Brunel to complete a second, more detailed survey, and finalise the purchase of necessary land. The cost of Brunel's route was £3,000,000 (equivalent to £309,000,000 in 2025), half of which had to be raised to propose the bill in Parliament. Brunel chose to route the railway north of the Marlborough Downs, which he chose for its preferential landscape and potential connections to Oxford and Gloucester, but it faced criticism for avoiding major towns. Once it became clear the necessary funds could not be raised within the parliament, the GWR decided to only propose the London–Reading and Bath–Bristol sections, postponing the rest of the line. The bill was submitted to Parliament in November 1833, and Brunel was called as a witness for eleven of the forty-two days of discussion. According to his biographer Annabel Gillings, he "flourished" under the pressure, making the hearing "a show [of which] he was the star". Nevertheless, the extent of opposition from landowners, settlements, and rival railway companies made the bill nonviable, and the House of Lords struck it down on 25 July 1834.

The main change made by Brunel to the bill was the terminus, from Vauxhall to meeting the L&BR at Queen's Park and using their terminus at Euston. It was while revising the bill that Brunel realised he could fix the swaying carriages on the Stockton and Darlington Railway by using a wider gauge of at least 6 feet 7 inches (2.01 m), and had any stipulation of gauge removed from the bill without telling the directors. Brunel's decision to use a wider gauge was controversial; his chosen broad gauge was 7 ft 1⁄4 in (2,140 mm), which he believed would offer superior running at high speeds. He found that the broader gauge was better for speed and comfort, but was less economical than narrower-gauge railways. Almost all other British railways to date had used a gauge of 4 ft 8+1⁄2 in (1,435 mm), yet Brunel said that this was nothing more than a carry-over from the mine railways that George Stephenson had worked on prior to his creation of the passenger railway. Brunel also argued that the wider gauge allowed for larger goods wagons and thus greater freight capacity.

The revised bill was particularly attacked by the London and Southampton Railway (L&SR), who wanted to protect their own plans for a railway between London and the West. Brunel's plans for the Box Tunnel in particular were very ambitious, and thus easily attackable, and so the L&SR claimed, with the support of Dionysius Lardner, that if a train ran away on the 1 in 100 (10‰) gradient, it would go so fast (120 miles per hour, 190 km/h) that the inhabitants would be unable to breathe. Upon Brunel's dismantling of these claims, the bill finally passed, and was given royal assent on 31 August 1835. It was only on 15 September that year that he revealed the change of gauge to the directors, whose approval was given on 29 October. In December 1835, the company decided to abandon sharing with the L&BR due to disputes between the companies, preferring to build their own station in Paddington, then merely a village on the outskirts of London. By the time the bill had passed, Brunel had already begun engineering works on other local lines such as the Bristol and Exeter Railway and the Bristol and Gloucester Railway.

1836–1841: Construction of the main line

By the end of 1837, the pressure of building the railway was beginning to affect Brunel. The GWR had made public in August 1837 their plans to open the line by November, which did not materialise. Brunel believed the next deadline set of 30 May 1838 to be impossible as well, but he was in fact wrong, and a private ceremony of the directors and others was held on 31 May 1838, in which the first train, the North Star, ran on the line between Paddington and Maidenhead. However, upon the genuine opening of the section of line on 4 June, problems quickly arose: the locomotives were not of good quality; Brunel's track design was uncomfortable; and the rails quickly shifted under the weight of trains because of Brunel's use of sand instead of stone for ballast. The directors concluded that the broad gauge was actually no worse than standard gauge railways of the time, but was not better as Brunel had promised.

If ever I go mad, I shall have the ghost of the opening of the railway walking before me, or rather standing in front of me, holding out its hand, and when it steps forward, a little swarm of devils in the shape of leaky pickle-tanks, uncut timber, half-finished station houses, sinking embankments, broken screws, absent guard plates, unfinished drawings and sketches, will, quietly and quite as a matter of course and as if I ought to have expected it, lift up my ghost and put him a little further off than before.

Other railway ventures

Brunel's other notable railway infrastructure includes the Windsor Railway Bridge, the seawall of the Exeter–Plymouth line, and the original Chepstow Railway Bridge. The Engineer wrote that the bridges were the most imposing part of Brunel's railways, and that his methods, though often criticised, were cutting-edge in their advancement of bridge-building techniques. Throughout his railway building career, but particularly on the South Devon and Cornwall Railways where economy was needed and there were many valleys to cross, Brunel made extensive use of wood for the construction of substantial viaducts; these have had to be replaced over the years as their primary material, Kyanised Baltic Pine, became uneconomical to obtain.

In 1832, Brunel was commissioned by the Bristol Dock Company to rebuild the locks on the entrance to their new floating harbour. The River Avon, whose tidality had impaired the function of Bristol as a port, was dammed and diverted, and the level of the docks was instead controlled by a series of locks. In 1842, Brunel began extending the width of the south lock, which is now eponymous to him and Grade II* listed; he used a single-panel gate design, which meant a new bridge needed to be built to allow people to cross into and out of the harbour. His design, the Brunel Swivel Bridge, was completed in 1850. In 1873, it was moved to its current position by the northern lock, and it was made Grade II* listed in 1972. It is included on Historic England's Heritage at Risk Register.

The 70 miles (110 km) of the Cornwall Railway between Plymouth and Truro crossed 45 rivers and deep valleys. Brunel spanned 42 of these with partly- or entirely-timber viaducts of various types. Workshops were established at Lostwithiel, with excess timber being used for the station buildings. The original viaducts are dated 1859, the year the railway opened, but many still on active railway have had their timber frames partially or entirely replaced. Between Saltash and St Germans, a deviation line was built in 1908, eliminating the wooden viaducts on the bypassed section of line. Those on the Falmouth branch were all replaced between 1923 and 1934. These timber viaducts allowed Brunel to build his broad gauge lines across challenging terrain at low cost, allowing him to expand them in vain of the increasingly-futile choice of gauge.

On 21 December 1850, Brunel was tasked by the GWR to rebuild London Paddington, which was quickly becoming too small for its traffic. He presented his preliminary design on 2 January 1851, and unusually for him, he was happy to work with other architects and engineers on the project, including Matthew Digby Wyatt. His relocated Paddington had a 700-foot-long (210 m) trainshed with ten platforms. While the first train departed on 16 January 1854, the project did not see completion until 1855. Alongside the new station building, new depots and offices were built, alongside the Great Western Royal Hotel, opened by Prince Albert on 8 June 1854.

In October 1827, Brunel began to write a personal diary, on top of the private diary and Thames Tunnel diary he already had, which he kept locked away to avoid intrusion. His personal diary is revealing of both a lack of self-confidence and self-satisfaction with the state of his career. He also discusses his thoughts for the future in great detail, stating that "indeed a bachelor life is luxurious", but that "on the other hand, in sickness or in disappointment how delightfull [sic] to have a companion whose sympathy one is sure of".

He was closely related to the Institution of Civil Engineers: he became an associate member in January 1829, a full member in 1837, was elected to its council in 1845, and was its Vice-President from 1850 until his death. On 10 June 1830, he was elected a Fellow of the Royal Society. Brunel's eldest sister Sophia married Benjamin Hawes, who would later serve in parliament as a Liberal politician; he and Brunel became close friends in spite of Brunel's disinterest in politics.

On 3 April 1843, while performing a conjuring trick for the amusement of his children, a half-sovereign coin which he had placed in his mouth became lodged in his windpipe. A special pair of forceps failed to remove it, as did a machine devised by Brunel to shake it loose. At the suggestion of his father, Brunel was strapped to a board and turned upside-down, and the coin was jerked free. He recuperated at Teignmouth, and his enjoyment of the area influenced his eventual choice of location for his country estate.

In the autumn of 1847, he purchased land in Watcombe in Devon, with the intent to build himself a country house; this would later become Brunel Manor. In comparison to the stress of his major engineering projects, working on the estate became what his brother-in-law John Horsley called his "chief delight". He commissioned William Burn to design the house and gardens; having a country home of this type had been a great dream of his youth. Brunel himself took great interest in the house and gardens and contributed to their designs, showing the closest attention to detail towards trees, whose growth and arrangement he would study to ensure the resulting estate was perfect. He died before the house or gardens were finished – only the foundations of the house had been completed by his death. Brunel did not leave his family enough money to finish the estate, and so they sold it off.

Marriage and issue

It was through Brunel's friendship with Benjamin Hawes that Brunel met his future wife, Mary Elizabeth Horsley, in summer 1832, whose family was accomplished in music and art; her father was composer and organist William Horsley, and her brother was John Callcott Horsley. John Horsley later praised Brunel's artistry, writing that he was "naturally imbued with artistic taste and perception of a very high order" and that he "had a remarkably accurate eye for proportion, as well as taste for form".

Isambard and Mary grew closer, and in May 1836, he proposed to her during a walk with her family on Holland Lane, London. The couple married on 5 July 1836 in St Mary Abbots, Kensington, before taking a honeymoon in North Wales and the West Country, and they established a home at 18 Duke Street, Westminster, overlooking St James' Park. The pair would live here until both of their deaths. Brunel's biographer Annabel Gillings comments that in contrast to Brunel's parents' intense, unfailing love, the partnership between Isambard and Mary was much more pragmatic and elegant. Isambard and Mary's children from their marriage were:

Isambard Brunel, born 18 May 1837. Born with unequal leg length, which Mary Kingdom Brunel refused to have corrected, he went on to become the chancellor of the Diocese of Ely.

Henry Marc Brunel, born in 1842. Henry went on to become an engineer himself, with his work including Tower Bridge.

Florence James née Brunel, born c. 1847. It was only through her marriage to Arthur James, a master at Eton College, that the family line was continued.

Death

Brunel was a heavy smoker, and Richard Bright diagnosed him with nephritis, to whose alternative name Bright's disease he was eponymous; this condition could lead to kidney failure if not treated, and Bright sent him to Egypt to recover there in the preferable climate, to which he left in December 1858 and returned in May 1859. By this point, he was ill enough that he could not stand, and in order to inspect the newly-completed Royal Albert Bridge he was taken across seated on a train. He also missed the banquet aboard the SS Great Eastern on 8 August as he was too ill to attend, but did inspect the ship on 5 September. It was during this inspection that the last photo of a by-then-frail Brunel was taken.Two hours later, Brunel suffered a stroke and was taken back to his home. On the evening of 8 September, he wrote his last letter, which asked for the GWR workers at Swindon Works to be given a day off to go and watch the SS Great Eastern. Four days later, on 9 September, he was informed of the accident on the Great Eastern and that it had killed five men. He did not survive long enough to hear the results of the inquest: at 10:30 pm on 15 September 1859, he died at his home in Duke Street, Westminster, aged 53. On 20 September, he was buried in Kensal Green Cemetery, alongside his father; the pair had designed the cemetery together in the 1820s. Brunel left his family an inheritance of £89,000 (equivalent to £9,670,000 in 2025), a much more modest sum than his railway contemporaries. Many mourned Brunel's passing, in spite of and because of his business ventures; an obituary in The Morning Chronicle noted:Brunel was the right man for the nation, but unfortunately, he was not the right man for the shareholders. They must stoop who must gather gold, and Brunel could never stoop. The history of invention records no instance of grand novelties so boldly imagined and so successfully carried out by the same individual.