Isambard Kingdom Brunel, the Great Western Railway and Pinus strobus L.
In 1805 the dispatches with the news of the great victory of Trafalgar and the death of Lord Nelson were brought by a Lieutenant Lapenotiere Royal Navy, firstly by ship and then by horse drawn carriage to the Admiralty. Less than a year later I K Brunel was born at Portsea in April 1806, born into the same world in which these two forms of transport dominated society. When he died in September 1859 he had, arguably, done more than any other individual to change the means of passenger transportation and moved it beyond imagination. Steam shipbuilding and railways dominated his career but it was his great facility with timber engineering which has largely gone unnoticed and allowed the ports of Cornwall to move to their potential. When we think of the Great Eastern, his two other ships and the Great Western Railway we could be forgiven for thinking that this was the sum total of Brunel’s career but it was within the GWR that his innovative genius lies hidden, particularly in his rail survey of the terrain between Bristol and Penzance.
The geographical topography from London to Bristol was challenging but difficulties were generally overcome by the use of a small number of tunnels and stone and brick structures, usually bridges and cuttings. The railway survey between Bristol, Falmouth and Penzance revealed quite a different picture, certainly in Cornwall a county that abounds with rivers and estuaries. We are reminded of this civil engineering challenge of building a railway system in Cornwall when we note the date on the Royal Albert Bridge, 1859. A comparatively late year when the advances in railway engineering in the years previously and key dates such as the Rainhill Trials and the Rocket locomotive are considered. To cross the River Tamar with a railway was to grasp the engineering nettle, a task that only Brunel could have accomplished at this time. For a few years, engineers of innovation and genius such as Brunel were able to direct civil, marine and mechanical engineering projects. His engineering contemporaries such as Joseph Locke and Robert Stevenson shared in a brief opportunity to practise as engineering polymaths. After Cornwall, the Great Western Railway and the link to Falmouth, no engineers of renown achieved so widely or with such visionary inspiration and innovative genius as Brunel.
Brunel demonstrated an ability to apply other technologies in particular circumstances to particular geographical terrains and to particular problems. The Atmospheric Railway from Exeter to Newton Abbott for example was ideally suited to the terrain but the materials available and material sciences were unequal to the task of overcoming nature’s abhorrence to securing a vacuum in the track cylinder. Brunel however, excelled in timber engineering and further, his contribution in this medium with his Cornish viaducts provided an indirect example, an impetus to American railways and the drive to the West by the Central Pacific Railway. Eventually, American railways were built at one fifth the cost of English railways despite paying higher wages all made possible by using the timber freely available in North America and adopting the technologies of Brunel.
"From the days when Cromwell ruled England until the Battle of Hampton Roads sounded the knell of wooden ships of war, the heads of the English Navy worried over its timber shortage". So claimed Albion in his introduction of "Forests and Seapower". What was perhaps more worrying to the English Navy was an adequate supply of suitable masting timber which could only be procured from abroad. Unfortunately in the midst of a maritime nation such as Britain these islands do not produce such timber, although there had been attempts to cultivate suitable masting timber in England, all of which failed. Pinus strobus L is the correct binomial, genus and species, for what is also called the ‘yellow pine’, ‘the eastern white pine’, ‘the white pine’ and the ‘Weymouth pine’, after Lord Weymouth who attempted to cultivate the species on his estate at Longleat. The attempted cultivation of Pinus strobus L at Longleat failed because of the parasite C. corticalis.(1) An attempt that reflects the urgency which the Royal Navy considered itself to be in during the American War of 1775 when the great mast supply from New England had ceased and the Riga masts had not yet arrived. Fortuitously, the situation had greatly improved by the era of Brunel and his search for a suitable timber for the Cornish viaducts. This timber was the key to unlocking the railway engineering difficulty to the county of Cornwall and to moving astride the many rivers and estuaries that Brunel’s railway must take.
In October 1831 Brunel experienced the Reform Act riots in Bristol and gave evidence at the subsequent trial of the Mayor, Charles Pinney. Ten years later, he also witnessed the huge timber fire at Temple Meads in 1841, caused by an attempt to make timber more durable by immersion in boiling creosote. Nevertheless, his assistant William Bell was given the task of finding a suitable timber for use in rail viaducts in the aftermath of the great timber fire and available in sufficient quantities for the Cornwall project. His recommendation favoured the masting timber Pinus strobus L, on which he had carried out extensive tests becoming eventually, something of an authority on the subject.(2) It is to the credit of Brunel that he would give such responsibility to his engineering assistants and explains to some extent why they later became eminent engineers in their own right after his death, certain beneficiaries of the great man’s tutelage and the frequency of hard responsibility in their careers. Brunel concurred with the selection by Bell of Pinus strobus L, a timber he was very familiar with and which he knew from his father’s engineering activities in the Royal Dockyards and the work of Sir Robert Seppings. This timber was a premier mast timber of the Royal Navy having an average length of one hundred and twenty feet, almost forty inches in diameter at the base, the single tree weighing close to eighteen tons. Importantly, it was freely available from North America and Newfoundland, and in sufficient quantities, based on a total timber project demand of at least 800,000 cubic feet, (16,000 timber loads) plus additional timber for repair, all at five shillings and seven pence the cubic foot. It would seem that the timber suitable for a main mast in a First Rate such as HMS Victory, would certainly be suitable for a viaduct crossing the River Lyhner at St. Germans in Cornwall. Brunel knew that he had fallen upon the technical solution to the Cornish project and of crossing fifty-one rivers and estuaries, but the railway unfortunately came too late to save the Falmouth Packet service.
Timber engineering in roof structures as well as timber rail viaducts reached an apogee and great climax in the vaulted roof of King’s Cross station in London. The roof had a span of one hundred and five feet and lasted seventeen years until it was dismantled. The Brunel timber roof at Bristol Temple Meads survives to the present day and the building is now the home of the British Empire and Commonwealth Museum. A survey in 1999 revealed that the timber used for the vaulted roof and his concept of incorporating arcades of Tudor arches was Pinus strobus L and built some twelve years before Paddington.(3) Brunel gave Bristol Temple Meads a hammer beam roof with span of seventy-two feet, five feet greater than Westminster Hall. This evolution in the use of timber as a structural material arose from a number of significant factors, chief of which was that it was a highly durable material and importantly, readily available. Timber imports from across the Atlantic continued to increase, made economically viable by the westward transportation of immigrants in a difficult, but nevertheless reciprocal trade. Consequently, durable timber collectively was far more available to the domestic timber market in 1830 and importantly, far cheaper in comparison to the traditional stone, cast and wrought iron. In addition this latter material, in the aftermath of the Tay Bridge disaster of December 1879 had lost the confidence of the public. Capital costs of construction could be halved by substituting timber for metal work in bridge and viaduct structures and this was the principle that Brunel followed assiduously. It is also worth noting that throughout the life of the timber viaducts in Devon and Cornwall, there was not a single passenger fatality. Another great attraction of timber was that it could eventually be substituted, when income from the railway service allowed, holding the line until an improved, more durable material could be found. Timber, while it remained sound, was never redundant , it could be used in a further application. The ‘false works’ of St.Pancras for example, scaffolding, was reused timber, vital in construction of the station, and an economically sound project. A further example is provided by timber beams in a beam engine, which were eventually substituted by cast iron beams, while the timber moved to yet another use.
The contribution made by Brunel to timber engineering was amongst his greatest achievements which had far reaching effects, the magnitude of which is not always recognised. In the past Brunel has been heavily criticised for his broad gauge rail system by John Latimer and more recently for his timber viaducts in Cornwall by John Binding,
(4) but perhaps the comments of Daniel Gooch, Brunel’s locomotive superintendent are noteworthy and seem to sum up the quiet approbation of British people when thinking of Brunel. Gooch claimed that Brunel was the greatest of engineers for whom duty to his country was everything, and who knew instinctively that great things are not done by those who sit down to count the cost of every thought and act, great things, great achievements are secured ultimately by men of visionary genius, such a man was Isambard Kingdom Brunel.
(1) W.Wren, Timbers and their Uses, (1919) p.127.
(2) W.Bell, Stresses of Rigid Arches, "Continuous Beams and Curved Structures", Procedures of the Institute of Civil Engineers. 33 (1876)
(3) Timber Research and Development Association Technical Report, Ref TT/F99106, dated 10 February 1999.
(4) A.Buchanan and M.Williams, Brunel's Bristol, (1982) p.97, see also J. Binding, Brunel's Cornish Viaducts, (1993) p. 132.
By Mike Baker
Add your comments
Please note: this is not an email facility, all comments are placed on
this page and on our Forum
Comment on this