Isambard Kingdom Brunel (9 April 1806 – 15 September 1859) was an English civil and maritime engineer who is considered by his biographers "one of the greatest figures of the Industrial Revolution", "perhaps the most eminent Victorian engineer", and one whose work "altered the lives of almost every person in Britain, and millions abroad". The first engineer of the Great Western Railway (GWR), he was responsible for the design and construction of its London–Bristol main line. His maritime career the construction of the largest steamships in the world at the time, the SS Great Western, SS Great Britain, and SS Great Eastern. His career was marred by continual financial and engineering setbacks. His first major project, the Thames Tunnel, was cancelled after a collapse nearly killed him, and was only completed later without his involvement. While recovering, he began his work on the Clifton Suspension Bridge; after riots in Bristol around government policy, work on the bridge was cancelled and it was only completed after his death.
Brunel's time at the GWR was hugely ground-breaking in railway design and the quality of railway construction, but was marred by frequent conflict with its board and figures such as Dionysius Lardner. Additionally, his choice to use a broad gauge of 7 ft 1⁄4 in (2,140 mm) ultimately led to huge problems for the GWR, and his attempt to convert parts of the network into an atmospheric railway were unsuccessful. His railway career involved his founding of many of the principles of a successful railway: his designs minimised curves and gradients, and his locomotives were streamlined. Brunel's construction of the Box Tunnel, the longest in the world at the time, was a success in spite of claims it would be impossible to construct safely. The Royal Albert Bridge was also eventually successful, but the lasting impact of the panic of 1847 meant Brunel had to simplify its design, and it was only completed shortly before his death.
Seeking to expand the GWR westwards toward the Americas, Brunel began looking at the prospect of developing steamships in the mid-1830s, and the three ships he built were each engineering marvels in their own right. The SS Great Western was the second ship to hold the Blue Riband, and her transatlantic crossings were commercially successful. The SS Great Britain was both the first iron-hulled and propeller-driven ship to make a transatlantic crossing, and was successful until her running aground in 1847 bankrupted her parent company. The SS Great Eastern was set back by conflict between Brunel and John Scott Russell and marred by financial and technical problems, with Brunel dying shortly after she suffered a huge explosion on its maiden voyage. She never saw commercial success except as a cable layer.
In 2002, Brunel was placed second in a BBC public poll to determine the "100 Greatest Britons", with a major programme of events celebrating the 200th anniversary of his death in 2006. Brunel is remembered as an engineering genius and visionary, whose maritime works in particular were too far ahead of their time to see success. His obituary in the Morning Chronicle remarked that "the history of invention records no instance of grand novelties so boldly imagined and so successfully carried out by the same individual".
Early life
Family
Isambard Kingdom Brunel was born on 9 April 1806 in Britain Street, Portsea, Portsmouth, Hampshire. He was the third child of his parents, and only son; his elder sisters were named Sophia and Emma and born in 1801 and 1804 respectively. At the time of his birth, his father was working on various projects for the Royal Navy in the area, including block-making machinery which employed the world's first production line. He was named Isambard after his father, the French-British civil engineer Sir Marc Isambard Brunel, and Kingdom after the English family of his mother, Sophia Kingdom; both of his parents had links to Normandy, where the Brunel name had been recorded since the 1400s. Brindle (2005) calls Marc Brunel "the most remarkable and able inventor living in Britain at that date".
Sophia, Brunel's mother, was an orphan for most of her childhood; her father, the naval contractor William Kingdom, died when she was young. Brunel's father, Sir Marc Isambard Brunel, was born in France; after making a royalist speech denouncing Maximilien Robespierre, he was forced into hiding with a royalist family, where he happened to meet Sophia Kingdom and they quickly fell in love and were engaged. Leaving for New York in September 1793, Marc spent 5–6 years in the United States finding work; in October 1793, Sophia was imprisoned in a convent for her royalist links and was only released upon Robespierre's fall in August 1794. The couple were reunited on 16 March 1799 and married on 1 November.
Shortly after Brunel's birth, the family moved to 4 Lindsey Row in Chelsea, London, which had been converted from Lindsey House. Marc Brunel devised many business ventures, such as making boots for the British Army in February 1809, which was successful until the government cancelled an order and refused to pay, leaving him with significant losses. Furthermore, the sawmill he had founded burnt down in August 1814, and he was unable to raise funds for its reconstruction.
When Brunel was 15, his father, who had accumulated debts of over £5,000 (equivalent to £475,000 in 2025), was sent to King's Bench Prison, a debtors' prison. Not wanting to abandon her husband, Sophia went with him. After three months went by with no prospect of release, Marc Brunel made public that he was considering working under Alexander I of Russia, which caused Arthur Wellesley, the Duke of Wellington, to warn the Chancellor they could not lose such an engineer. In response, the Chancellor relented and issued Marc the £5,000 to clear his debts, in exchange for his promise to remain in Britain; the couple were released in August 1821. Brindle (2005) makes the comparison in this respect between Brunel and Charles Dickens: both were of a similar age; both were from Portsmouth; both had fathers sent to debtor's prisons; and both spent their early adulthood in London.
Education
In spite of his family's tumultuous finances, Brunel had a happy childhood and education, with his father acting as his first teacher. His father taught him drawing and observational techniques from the age of four, and Brunel had learned Euclidean geometry by eight. During this time, he learned to speak French fluently and the basic principles of engineering. He was encouraged to draw interesting buildings and identify any faults in their structure, and like his father he demonstrated an aptitude for mathematics and mechanics.
When Brunel was eight, he was sent to a school ran by a local Reverend Weeden Butler. He was then sent to Dr Morrell's boarding school in Hove, where he studied classics. His father was determined that Brunel should have access to the high-quality education he had enjoyed in his youth in France. Accordingly, at the age of 14, the younger Brunel was enrolled at the Henri Quatre (Henry IV) College in Caen, where he remained for two years. During his time at the school he was seen to be interested in helping his father with his work and was very proficient in calculations. Nevertheless, he was also fond of artistic in addition to engineering drawings. He then went to Lycée Henri-IV in Paris, which was known for its mathematics education. While abroad he was easily sheltered from his parents' imprisonment, but having been imprisoned for his debts, it is impossible Marc Brunel could have paid for his son's education; the benefactor who did remains unknown.
When Brunel completed his studies at Lycée Henri-IV in 1822, his father had him presented as a candidate at the renowned engineering school École Polytechnique, but as a foreigner, he was deemed ineligible for entry. At the time, there were no university degrees in the United Kingdom in engineering or mechanics, and so Brunel decided to stay in Paris and study under the prominent master clockmaker and horologist Abraham-Louis Breguet, because horology was the finest type of engineering. Breguet praised Brunel's potential in letters to his father; in August 1822, having completed his apprenticeship, Brunel returned to England.
Early career
1823–1824: First projects
Brunel continued his engineering education in England by becoming an assistant to his father from 1823, which allowed him to work on significant engineering projects. In this time, he helped his father with building the bridges on the French island of Réunion (then the Île Bourbon), a design for a potential Panama Canal, the concept of a floating pier for the Port of Liverpool, and working with Augustus Charles Pugin to design Kensal Green Cemetery. While during this time Brunel's career was calm and stable, he also became impatient that he was not yet prominent and successful.
In spring 1823, Brunel's father came up with an idea for a so-called Gaz Engine [sic] which was an alternate design to the steam engine. The idea was based on an experiment by Michael Faraday in which gases such as carbon dioxide could be liquefied under high pressure and upon being heated, they would boil and massively expand in volume, hence producing the force to drive the engine. The benefit of this in comparison to the steam engine was that there was no smoke released so it was more pleasant to run, and that it would supposedly be significantly more efficient.
Brunel and his father then tried to produce this Gaz Engine at a huge cost, yet Nicolas Léonard Sadi Carnot's work on thermodynamics at around the same time would prove such an engine impossible. However, this work was not yet understood in the United Kingdom, and so Brunel and his father continued to work on it in vain, receiving funding from the Admiralty and Faraday himself. By January 1833, he had finally abandoned his ideas of the Gaz engine, writing in his diary that "All the time and expense both enormous devoted to this thing for nearly ten years are therefore wasted".
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 the Thames Tunnel project, which would aim to build a tunnel under the river Thames. Described by his biographer 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 its bridges, the latter 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 in 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 how to overcome the 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 then use their faeces to fill in their own path, preventing 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 reinforce the tunnel. Only one person would mine at a time, and that person would only uncover, mine, and recover one section at a time; once all 48 sections were complete, the shield was moved forward. 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 the digging of two separate tunnels 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 for himself. Due to early setbacks the company pressured for the tunnelling to happen faster, and so the construction became even more dangerous. The pollution in the tunnel from sewage in the Thames poisoned the workers; Brunel and his father offered to help with the construction themselves nonetheless.
In April 1826, John Armstrong resigned due to the illness and fatigue of the project, and 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 critical one point in September 1826, he refused to leave the tunnel for a total of ninety-six hours, which he spent working with occasional breaks to sleep. Brunel decided he would respect the toil of the workers and horrible conditions by joining them, going as far as living in a cabin inside the tunnel with one of his assistants. He spent most of his time monitoring the progress and quality of construction and ensuring the workers' discipline.
On many occasions Brunel himself risked his life swimming out to rescue one of his workers. On one occasion, while still recovering from an earlier rescue, he visited the workmen during their dinner and was received with applause, and their wives cut pieces of his coat off to keep as relics. However, his hardest task as Engineer was dealing with the Thames Tunnel Company, who far 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 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, during which time he began a design for a bridge in Bristol, which would later be completed as the Clifton Suspension Bridge.
Brunel was too ill to continue on the tunnel and left the project. The second collapse stopped work on the tunnel for several years, and it was bricked up in August 1828 while negotiations on its construction continued. Work on the tunnel would not resume until 1835, and was finished in 1843 to a different design than Marc Brunel's. Brunel had no further involvement, only using the abandoned works at Rotherhithe as a site for Gaz Engine-related experiments; he was left depressed by the failure of his first major project. 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 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 for the bridge was decorated with Egyptian designs, such as sphinxes and hieroglyphs; he also included large panels detailing how the bridge had been constructed. Both Brunel and Telford lost to W Hawks, with Telford not even being 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 was entirely cancelled.
Brunel did not live to see the bridge finished, although his colleagues and admirers at the Institution of Civil Engineers felt it would be a fitting memorial, and started to raise new funds and to amend the design. Work recommenced in 1862, three years after Brunel's death, and was completed in 1864. While the bridge was built to designs based on Brunel's winning entry, it had significant changes. The final bridge spans over 702 ft (214 m), and is nominally 249 ft (76 m) above the River Avon; therefore, it had the longest span of any bridge in the world at the time of construction. To what extent the final bridge's design was really his is discussed by historians: his biographer Adrian Vaughan suggested in 2011 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 Gillings (2006) suggests that "only a fraction of [Brunel's] design is visible", and points out that his decorations were never added. However, Harrison (1886) 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. Brunel's own family were offended when the new design was shown at the 1862 International Exhibition, arguing his own contribution had been underplayed.
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 the railway picked up the support of local groups such as the Society of Merchant Venturers. While the Clifton Suspension Bridge remained incomplete for Brunel's life, 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".
The company committee did appoint Brunel in March 1833, but only alongside William Townsend, whose only experience was tramways in the Bristol area, and with whom Brunel had no interest in working. Brunel and Townsend were given ten weeks to travel the entire route on horseback, take the necessary measurements to work out the route, and convince the landowners to sell the land needed to build the railway, many of whom were starkly opposed to a railway cutting through their property or area. The project was publicised on 30 July 1833, the longest ever proposed at 116 miles (187 km). Brunel felt the directors were not enthusiastic enough, bar one, Charles Saunders, with whom he 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), of which half had to be raised to successfully propose the bill in Parliament. Brunel's route was criticised because it passed north of the Marlborough Downs, an area with no significant towns, because Brunel preferred its landscape and thought it offered potential connections to Oxford and Gloucester. When it became clear raising the necessary funds was impossible within the parliament, the GWR decided to only get permission for London–Reading and Bath–Bristol, 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 Anabel Gillings, "he flourished under [the pressure]" and "made it a show, [of which] he was the star". Nevertheless, the extent of opposition from landowners, the settlements along the route, and rival railway companies, left the bill unviable and the House of Lords voted to oppose it 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 this changed on 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 narrow- or standard-gauge railways. Almost all other British railways to date had used standard gauge, 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 construction of the world's first 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, as by this time they had their own plans for a railway from London to the West. Brunel's plans for the Box Tunnel were very ambitious, and therefore easily attackable, and they 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 and build their own station in Paddington, which would eventually become the modern station. 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, but this 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 were 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.
Under pressure from the GWR board to work out how to improve the track, a report was given by John Hawkshaw, whose poor research led him to believe the problem was that the locomotives were too powerful for the track. A second report by Nicholas Wood, with the help of Dionysius Lardner, concluded the issues was the number of piles and that broad-gauge trains led to too much drag. The GWR, in response to the reports, decided Brunel needed to work alongside another Engineer to prevent further shortfalls; Brunel said he would rather resign, and would prove his worth in his completion of the line. Firstly, Brunel modified the design of the North Star, to improve its speed, after which it could go 38 miles per hour (61 km/h), which was physically faster than Lardner's calculation for Wood's report would allow, and Brunel was kept, alone, as Engineer by a vote of the shareholders, along with his broad gauge design. Brunel believed that once the GWR had expanded sufficiently other lines would conform to what he saw as the superior gauge.
One of the most notable structures on the line was the Maidenhead Railway Bridge, the flattest-arched bridge ever built at the time of its completion. The design of the bridge was deemed impossible by some, and after the supports were withdrawn prematurely by the bridge's builders it began to sag. After it had been repaired, Brunel left the supports there, but not actually holding the bridge, to allow his critics to revel in his supposed failure; the supposedly necessary supports were then destroyed by storm, revealing the functional bridge behind, which Brindle (2005) described as a "heroic affair". The bridge is still functional today despite trains being up to ten times heavier.
Brunel's Western terminus at Bristol Temple Meads was also an innovative element of the line, which began the practice of the railway station as an integrated multi-purpose hub, rather than simply an infrastructural necessity. Brunel quickly expanded the line west through Didcot; he was constantly battling the GWR board, who though his plans overambitious and unnecessary. After the board saw his design for Reading railway station in April 1839, they refused to approve it because of its scale, and Bristol Temple Meads was rationalised too later that year.
In this time, Brunel let his assistant Daniel Gooch work independently of him and the board on increasing the capability of the locomotives from their original designs; in 1840, a driver was fined by the company for racing locomotives and while Brunel at first said the practice "must be put to a stop immediately", he soon changed his mind and refunded the driver. On 13 September 1840, Gooch wrote to Brunel suggesting they build a locomotive works at Swindon as they were running out of space at Paddington station. Rather than just building a works, Brunel built an entire new town for its workers named "New Swindon", which opened with the works on 2 January 1843.
While the quality of his locomotives and the railway had increased, Brunel was nonetheless severely over his budget and delayed on building the rest of the London–Bristol line. Two deadlines of August 1840 and February 1841 had gone by, by which point there were still significant gaps in the line, in particular the Box Tunnel. With the opening of the Box Tunnel, the line from London to Bristol was complete and ready for trains on 30 June 1841; the first journeys took 5+1⁄2 hours compared to road journeys of 15–20 hours, but the final cost was £5,887,000, equivalent to £528,000,000 in 2025.
1842–1846: Railway Mania and the Gauge War
By the 1840s, the United Kingdom was in Railway Mania—Parliament passed 650 railway acts between 1845 and 1848, and engineers and railway companies were desperate to find alternatives to steam engines. One consequence of this was that railways were beginning to branch out, with Britain covered in small lines. As these lines began to link up, a problem arose for the GWR whose broad gauge was incompatible with most other railways' narrower gauge. On the one hand, Brunel's broad gauge railway was simply faster—the first London to Exeter train covered 194 miles (312 km) in 4+2⁄3 hours, making the GWR's services the fastest in the world at the time, but they were simply outnumbered by the rest of the country. Brunel's general engineering influence allowed him to spread the broad gauge in the West and Wales, such with as the South Wales Railway, of which he became Chief Engineer in 1844. As these railways then spread north and east it created huge issues: locations such as Gloucester and Swindon were served by railways with different, incompatible gauges, and goods trains would wait for hours as their cargo was transferred between different-gauged wagons.
In July 1945 a royal commission was created to research the optimum gauge for the country, by which time it had picked up the name of the "Gauge War". The commission began their hearing on 6 August 1845 and Brunel was called to give evidence from 25 October. Brunel's argument was twofold: firstly, no single gauge was needed because such a war created beneficial competition between companies; and secondly, that the broad gauge was, as Brunel had always claimed, a better choice of engineering because it allowed for faster and more comfortable services. Brunel naively suggested a race between locomotives of each type, even though the newest broad-gauge locomotive was three years of age compared to many newly-built narrower gauge locomotives. Engine A, representing the narrower of the gauges, ran the 44-mile (71 km) Darlington–York section of line, whereas Ixion, a Firefly class representing the broader of the gauges, ran the 53-mile (85 km) Paddington–Didcot section of line. Despite its older age, Ixion kept an average speed of 53 miles per hour (85 km/h); when Engine A reached this speed on its run, it derailed.
In spite of the evidence Brunel sought to demonstrate, their report, published in 1846, was in favour of the narrower gauge to become the new 'standard gauge'. The commission argued the most important factor was having only one gauge in the country, and the hassle of converting the narrower gauge to the broader gauge was significant compared to the opposite. Brunel refused defeat and lobbied Parliament with his own fifty-page report on why the commission was wrong to choose against him, and while the decision was not reversed, Parliament permitted Brunel and the GWR to continue building in his gauge. His adamance that his gauge was better from an engineering perspective eventually became irrelevant in the face of its financial inferiority; the GWR would eventually convert their broad gauge track to the new standard gauge, starting in the 1860s after Brunel's death and finishing in May 1892. In the modern day, some high-speed railways have reverted to broader gauges, such as the Japanese Shinkansen.
It was during this period that Brunel designed the first Hungerford Bridge, the purpose of which was originally to serve the newly-renovated Hungerford Market. An act of parliament had been approved in 1836, and the land bought in 1840. The bridge was constructed between 1841 and 1845, and upon opening on 1 May 1845, it was a pedestrian-only suspension bridge. Brunel designed the bridge with two piers in the river, built from brick and in an Italian style, and using chain suspension. In 1859, the replacement of the bridge with a railway bridge to serve the new Charing Cross railway station was approved, and the dismantling of the old bridge began in 1860. The chains and ironwork were used in the eventual construction of the Clifton Suspension Bridge after Brunel's death.
1847–1848: The atmospheric railway
It was in the context of the Railway Mania that Brunel chose to build the Atmospheric Railway. In 1844, Brunel had travelled with Gooch to Dún Laoghaire to visit their so-called 'atmospheric railway'. Invented by Samuel Clegg as an adaption of a similar system for moving post, each trains had no engine and was instead connected to a pipe. Air was pushed through the pipe by huge pumps at each end of lines, which contained the steam engines. One direction of line was uphill, using the pump system; the other was downhill and gravity based. At the same time, the South Devon Railway (SDR) was building a line between Exeter and Penzance; this line was an independent company but would carry through trains from the GWR. Brunel realised that he could use this atmospheric system on the SDR, and planned to build a test section as far as Teignmouth. The atmospheric railway had many flaws—the driver had little control of the train, which could lead to deadly accidents, and keeping the pipes airtight over long distances was difficult. Both Brunel and William Cubitt believed in applying the concept to the British railways; George and Robert Stephenson thought it too impractical, as did Gooch. The piping was so expensive that Brunel had to reduce the line to a single-track, and it opened to Teignmouth after delays on 13 September 1847. The line was built with pumping stations at 2-mile (3.2 km) intervals, designed with distinctive square chimneys; engine houses were also built further towards Plymouth and on the Torquay branch (now the Riviera line). There were eight pumping houses in total on the route. 15 in (380 mm) pipes were used on the level portions, and 22-inch (559 mm) pipes were intended for the steeper gradients.
The line had reached Newton Abbot by 10 January 1848, with trains able to run at approximately 68 miles per hour (109 km/h). Nevertheless, Brunel was proven wrong—the valve connecting the train to the pipe leaked constantly, and the pipe both froze solid in winter and was eaten by rats. Yet it was the deterioration of the valve—due to the reaction of tannin with iron oxide—that was the last straw that failed the project, as the continuous valve began to tear from its rivets over most of its length, and the estimated replacement cost of £25,000 (equivalent to £2,573,000 in 2025) was considered prohibitive. The railway closed for conversion back to a normal railway on 10 September 1848, having operated for less than a year, and Cubitt's line in London had closed the previous year equally as unsuccessful.