By Bill Rogerson
2020 Marks the 170th Anniversary of the Opening of The Britannia Bridge on 5 March 1850, and 50 Years Since the Disastrous Fire on the 23 May 1970
Part 2: THE BRITANNIA BRIDGE
After many years of deliberation and proposals, on the 30 June 1845, a Parliamentary Bill covering the construction of the Britannia Bridge received royal assent. Robert Stephenson, son of George Stephenson, was appointed Chief Engineer for the construction of the bridge.
Prior to building the Britannia Bridge, Stephenson built a tubular suspension bridge over the river Conwy in the town of Conwy. It could be said that this was a prototype for the much larger Britannia Bridge. Conwy is unique in having three great masterpieces side by side. Edward the First’s castle, begun in 1283, Thomas Telford’s suspension bridge and Robert Stephenson’s the first ever railway tubular bridge ever built. These three mighty structures are still in use today a testament to the engineering of the time. Thomas Telford’s bridge, with castellated tops to blend in with the castle, was used for road traffic until 1959 when it was replaced by a third bridge. Since 1988 a lot of the road traffic uses a tunnel under the river Conwy, constructed to ease the amount of traffic using the medieval town. The railway station opened on 01 May 1848 was closed on 14 February 1966 but reopened on 29 June 1987. Between 1848 and 1966 the anglicised name of Conway was used on the station nameboards. But on reopening it was spelt the Welsh way Conwy.
The Britannia Bridge was intended to link the mainland just west of Bangor to the Island of Anglesey (Ynys Môn), making use of the Britannia Rock midstream. (This is from where the bridge takes its name). As the Menai Strait was still a navigable channel towards the Irish Sea, Stephenson actually wanted to build a wrought iron bridge over the straits. The Admiralty stipulated that any bridge crossing the straits should pose no obstruction to shipping during construction and must have headroom of 105 ft (31.5m) above high-water level.
His idea for a tubular bridge came in 1841. He had designed and built a small tubular bridge by rule of thumb methods which spanned the river Lea at Ware on the North East Coast. He did not seriously consider this design until fate stepped in with one of those extraordinary co-incidences that it sometimes favours the brave and courageous.
A 180 ft long, iron steamship, named Prince of Wales was being built at a shipyard on the River Thames. A bolt holding a cleat sheared and the bilge of the ‘Prince of Wales’ came down on the wharf and the stern tipped downwards as she was being launched. The vessel could not be freed for several hours. The incident was related to Robert Stephenson and he saw the answer to the problem as if the ship could be suspended for 110 ft and suffer no damage, then he would build his bridges as tubes on land and then float them into position. In fact, that is what he did, built iron ‘ships’, lifted them into position and used them as bridges: but engineering knowledge and science had to be developed by others before his dream could be accomplished. Stephenson’s initial ideas were for a circular or elliptical tube.
He had further discussions with Sir William Fairburn a Scotsman who settled in Manchester, an Engineer of Canal Street Works, Ancoats, Manchester. Following extensive trials, a suitable design, a rectangular tube with a cellular base and a roof for added strength was eventually adapted and used in the construction of the Conwy bridge. The tubes for Stephenson’s convenience, were built at Fairburn’s Millwall works on a one sixth scale model 80’ long, 4’-6” deep and 2’8” wide with supports 75’ apart. This was then loaded with weights and the deflection measured. It was found that the tubular construction enabled the bridge to support eleven times its own weight. Other tests were then carried out at Canal Street. William Fairburn and his men did their work well, for in those days’ trains were similar to ‘The Rocket’ and yet today, the 10 coach ‘Voyagers’ and others cross the original bridges in tribute to the Victorian Engineers.
So, following the successful construction of the Suspension Bridge at Conwy, he decided upon his tubular design for the Britannia Bridge; the railway line running through tubes, made up of wrought iron riveted plates. The bridge consisted of two main spans of 460 ft and two smaller spans at each side of 230ft, all supported by masonry towers, the tallest being the Britannia Tower at 221 ft.
Stephenson believed that suspension bridges were too flexible to carry the weight of trains in safety. At that time (40 years before the Forth Bridge) no known type of beam truss or bowstring girder bridge had been proved sound above a quarter of the span required for the Britannia Bridge.
Building a bridge of unprecedented span with such thorough techniques placed an immense strain on Stephenson, who remarked: “All night I would lie tossing about, seeking sleep in vain. The tubes filled my head. I went to bed and got up with them”. The hard work did, nonetheless, bear fruit. It proved, for example that chains could be dispensed with and that the planned circular or elliptical tubes should become rectangular with cellular tops and bottoms for greater rigidity. Moreover, they were to be built to act as continuous girders over four spans, an unprecedented application of beam action.
By this stage the masonry piers, with rectangular slots at the top started in 1845, had been constructed to the height required for a suspension bridge – just in case Stephenson found a way of incorporating the necessary rigidity in such a structure. As a result, the completed four-span bridge of iron and brick, with three colossal Egyptian-style pylon towers, built using Anglesey marble, weighing between 10 and 12 tons each. The interior was of Runcorn sandstone, supporting an immense rectangular tube, had a grand, aesthetically pleasing appearance.
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Two complete villages were built on either side of the Straits near to the site for the bridge, including huts for the men, shops, schools for the children and a chapel of worship. There were some complaints about the prices of the goods in the shops but in general the villages were almost self-supporting.
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Work began on the Britannia Bridge across the Menai Straits, when the first stone was laid in May 1846. The first rivet was hammered in on the 10 August 1847 and at a time when photo opportunities were unknown the last 2,000.000 rivet was hammered in by Stephenson himself on the 5 March 1850 in a symbolic display before an appreciative audience. and to this day is painted white. The engineers now had a proven method of making and positioning the tubes. The Straits were and still are very difficult waters to navigate as any mariner will testify.
In this design, Stephenson was assisted by three men, William Fairburn (in designing the distinctive ‘tubes’ through which the trains originally ran), Eaton Hodgkinson, a mathematician (who investigated the strength of the tubular structure) and Edwin Clark (Stephenson’s resident engineer).
Stephenson was not happy about floating the tubes into position at Conwy, Edwin Clark was very persuasive and finally convinced Stephenson that it could be done with proper planning and with the right man in charge of the marine operation. The man chosen for this task was Captain Claxon RN, who had achieved fame by building Isambard Kingdom Brunel’s ship ‘The Great Britain’ the mightiest ship ever built at that time. Claxon who was involved in the construction of the Conwy Bridge, was also appointed to the team for the Britannia Bridge.
Each tube was 472 feet long and 98 feet high, and some of the navigational problems may be gained by noting that each tube was three times as long as the largest ship then afloat anywhere in the world at that time – The Great Britain . The two longest tubes were built in sections on the Caernarfon shore, some 600 feet from the permanent site and were floated into position using pontoons then raised onto the towers using a hydraulic jack. Once in position they were joined inside the tower making a continuous beam of 1511 ft – at the time the longest wrought iron span in the world.
Large pontoons with giant capstans bolted to them were towed out into mid-stream and anchored there. Each capstan was worked by fifty men, hawsers passed around the capstans from the shore and the masonry tower. There were no less than 600 men employed in the floating and positioning of the tubes and of this number three hundred and eighty-six were sailors from Liverpool. Because of the distances involved in between the various teams of men, Captain Claxon evolved a system of signalling by means of boards with numbers and letters painted on.
On the 27 June 1849 at around 19.30 hours the first tube was floated and prepared for lifting. Strong winds and tides almost ended in catastrophe as the 1,5000 tons iron appeared to be in danger of being swept away down the Menai Straits.
The crowd of people that had gathered on both sides of the Straits to watch this momentous occasion pulled together to rescue the situation by entering into what has subsequently been called the most desperate tug of war ever, by holding onto the supporting cable. The spectators seemed spellbound for no shouts or exclamations were heard, as all watched silently the silent course of the heavily freighted pontoons. The only sounds heard were the shouts from Captain Claxon as he gave directions to “let the ropes go”, “to haul in faster” etc and broadside on the tube floated majestically into the centre of the stream.
Robert Stephenson made his first journey across the Britannia Bridge together with an estimated 1000 passengers on the 5 March 1850. As far as I can ascertain the bridge was not officially opened by a dignitary and certainly not by a member of the Royal Family. And the whole route was opened to through trains between Chester and Holyhead on the 18 March 1850. The 2.30 pm Holyhead to London Euston express was the first public passenger train to travel the whole of the Chester and Holyhead Railway.
By that time, all various elements of the route between the English Capital and Holyhead had been amalgamated to form the London & North Western Railway, bringing the ferry port within five hours of London. The installation of wooden decking over the tube to protect the metal from the sun represented the final stage of the work, but, long before this was finished, Stephenson, Fairburn and Hodgkinson were already quarrelling over who should claim credit, for completion of the project.
It was nevertheless a remarkable achievement by the three men, who had designed and created a novel bridge in an incredibly short time and advanced the understanding of materials – wrought iron in particular – to the extent that the railway bridge design moved from being purely empirical to an exact science The second tube was opened to rail traffic on the 21st, October 1850.
After the bridge was completed, the great hydraulic cylinders that had been used for lifting the tubes were exhibited at the Great Exhibition of 1851 held in the Crystal Palace Hyde Park, to take stock of the products of the Industrial Revolution and of Victorian achievement.
The Britannia Bridge took four years to build and was the most vital piece in the Chester and Holyhead Railway jigsaw. It cost £601.865 some three times over budget. The navigation lights affixed to either side of the bridge on the Britannia tower are maintained by Network Rail.
A section of tube from the original structure is still in existence and can be found on the mainland side quay. There are plans to move it to a more accessible place for the public to view it. Similarly, with the bridge at Conwy, Stephenson’s Britannia Bridge can be seen from Telford’s delicate and elegant road bridge.
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An impressive set of lithographs show’s Britannia Bridge’s construction, reflecting careful observation of the engineering processes and of the men involved in the successive stages of the work. These superb impressions of the project’s magnitude were the work of George Hawkins, a former architectural draughtsman. another lithographer attracted to Stephenson’s great pioneering work was Samuel Resell, who depieced various scenes on the Chester and Holyhead Railway’s construction, including a detailed view of one of the tubes being constructed on the shore of the Menai Strait. It was not until 1934 that a really clear overview of the bridge was produced with an aerial perspective showing the magnificent feat blending harmoniously with its setting. This was the work of Norman Wilkinson who, using a limited range of colours , created a stunning poster for the LMS showing the ‘Irish Mail’ coming off the bridge and passing between the pair of huge stone lions; noble guardians of the Britannia Bridge that provided the finishing touches to Stephenson’s masterpiece.
In 1973 the British Transport Film Unit produced a 19 minutes colour film entitled ‘Britannia – A Bridge’, showing the reconstruction of the bridge. This film is available through the British Film Institute.
There was originally a railway station located on the east side of the bridge at the entrance to the tunnel, run by the Chester and Holyhead Railway company, which served local rail traffic in both directions. However, this station was closed on 1 October 1858 after only 8 1⁄2 years in operation owing to low passenger volumes. In the present day, little remains of this station, other than the remnants of the lower-level station building. A new station named Menai Bridge on the mainland was opened shortly afterwards. This was closed on the 14 February 1966.
GUARDING THE BRIDGE – THE LIONS
The bridge was decorated by four large lions sculpted in limestone by John Thomas, two at either end. These were immortalised in the following Welsh rhyme by the bard John Evans (1826–1888), who was born in nearby Menai Bridge:
The lions cannot be seen from the A55, which crosses the modern bridge on the same site, although they can be seen from trains on the North Wales Coast Line below. The idea of raising them to road level has been suggested by local campaigners from time to time. A few years some vandals decided to give the lions a manicure, they painted their toes bright red.
Part 1: The Chester and Holyhead Railway
Part 3: The Britannia Bridge