After the completion of the Great Western Railway from London to Gloucester in 1845 the South Wales Railway Company was formed to finish the route via Newport and Cardiff to Milford Haven, in order to complete the line, Isambard Kingdom Brunel was asked to design a bridge to cross the River Wye. The problem was complicated by Admiralty constraints requesting a navigable opening 300ft wide, with head room of over 50ft at high tide. This was necessary because at that time the Wye was navigable up to Brockweir by vessels of sixty tons and by barges of forty tons as far as Monmouth.

Before this bridge was built, the South Wales Railway ended on each side of the river and passengers had to make a connection between the two sections by travelling in a stage coach over the Wye road bridge. It was Brunel’s much needed bridge that enabled this gap to be filled.

The main problems involving the design of this bridge was the massive tidal range of 48 feet, the instability of the river bed which rests  on 50 feet of sand and gravel, and the difference in level between the limestone cliffs on the Tidenham side and the Chepstow bank at low tide. 

Construction of the bridge began in 1849 and because there was poor ground on the Chepstow side, Brunel had to provide firm foundations. He did this by sinking a pair of elevated wrought-iron tubes, side by side, supported at one end upon a tower. This rested upon cast-iron cylinders, sunk, using compressed air, to an average depth of 48 feet through clay, quicksand and marl to be embedded on solid limestone rock.  

The construction of this bridge involved some new engineering features and in particular, each track was supported by an iron tube 100 yards long. It is of interest that the components of the bridge were manufactured in Chepstow by Edward Finch, who subsequently invented the first metal mast to be used by the British navy. Brunel’s famous steam ship, the Great Western was also fitted with iron masts, and these were made in Chepstow.  

The bridge was built at a cost of £65,420 and  Brunel was a passenger on the first experimental train that crossed the bridge on 15 July 1852. The first fare paying passengers crossed the bridge 4 days later, travelling from Swansea. A second line was opened on 18 April, the following year.

In 1962 it was decided that Brunel’s tubular railway bridge had become unsafe because it was not strong enough to carry today’s heavy trains, so it was strengthened by the replacement of the 300ft iron tubes by new trusses underneath. These were machine-welded in the adjoining shipyard of the Fairfield Engineering Company, They were then assembled on site with high strength bolts, without interfering with the train services running above.

Chepstow Railway Station, constructed in 1850, is one of the few original remaining stations designed  by Isambard Kingdom Brunel. The platforms are very far apart having been built for his Great Western Railway which initially used the 7ft broad gauge. 

In 1872 Brunel’s broad gauge tracks were replaced with George Stephenson’s standard gauge of 4ft 8ins. But there were complaints about the gap between the trains and the platforms, so the platforms were raised and in 1857, the station building, weighing about 150 tons was also raised.

Access to one of the platforms is via a cast-iron footbridge which is a rare survival of a typical GWR platform foot bridge with wooden cladding and canopy (now corrugated iron). Grade II listed it was cast in Edward Finch’s works, adjoining the station in 1892.

The Stow Hill railway tunnel at Newport was engineered by Isambard Kingdom Brunel for the South Wales Railway, which was one of the most important of the early routes into Wales. The first train to pass through the tunnel was on 18 June 1850. 

It takes the railway line under Stow Hill from a point south of Newport Station and emerges 742 yards away near Llandaff Street. The contractors were Messrs Rennie and Logan, who employed 400 men and 50 horses on this project. 

It consists of a pair of semi-circular bores of approximately 680 metres in length. The earliest East Bore dates from  the construction of the line in 1846-50 and is Grade II listed. The parallel West Bore dates from 1911 and was built in order to double the track. The interior of both tunnels is faced in stone. The two portals are different in design; the one which was opened in 1848 as a broad gauge route was built by the South Wales Railway and sponsored by the Great Western Railway. The other one was  built in 1910 on the north side in order to widen the route to four tracks.  

Isambard Kingdom Brunel, was the son of the famous inventor, Sir Marc Isambard Brunel and Sophia Kingdom. Sir Marc’s greatest achievement was the design and construction of the Thames Tunnel, which led to his knighthood. His more famous son,  born in Portsmouth in 1806 was undoubtedly a child genius, who became one of the most important figures in engineering history. In a 2002 poll by the BBC, he was rated the second greatest Briton of all time (after Winston Churchill). His feats and achievements revolutionised how we approach engineering, transport and construction.

He built twenty-five railway lines, over a hundred bridges, including five suspension bridges, eight pier and dock systems, three ships and a pre-fabricated army field hospital. Some of his most famous projects include the Great Western Railway, the SS Great Britain, the SS Great Eastern and the Clifton Suspension bridge.

In 1833, Brunel was appointed Chief Engineer of the Great Western Railway which was built to link London to Bristol and included the 1.8 mile long Box Hill Tunnel in Wiltshire, the longest railway tunnel in the world at that time.

His nick-name was ‘the Little Giant’ because he was a highly mobile bundle of energy who was able to manage several projects at the same time. He was only 5 feet tall and being very self conscious about his height, he would often wear a stovepipe hat, 8 inches high in order to look taller. Such hats were made very popular in the United States by President Abraham Lincoln, who often carried documents and letters inside his hat! 

Isambard Kingdom Brunel had a stroke whilst standing on the deck of the Great Eastern and died on 15 September 1859 aged fifty-three. He was buried in the Brunel family vault at Kensal Green Cemetery, London. A memorial plaque to him can be seen at each end of the Royal Albert Bridge at Saltash which opened just a few months before his death.