The Early Pioneers – Bridges, Canals, Railways and Ships.

The Early Pioneers – Bridges, Canals, Railways and Ships. Presented by Professor F.M. Burdekin FREng, FRS. On 24th October 2006 Abstract The paper reviews the work of some of the engineering pioneers of the eighteenth and nineteenth centuries, particularly comparing the achievements of Thomas Telford, George and Robert Stephenson and Marc and Isambard Kingdom Brunel. The Background of World Events The second half of the eighteenth century and the whole of the nineteenth century were periods of great change in the United Kingdom – the Industrial Revolution. Things were happening elsewhere in the world as well. American Independence was declared in 1776 and the French Revolution took place between 1789 and 1799. England was at war with France between 1797 and 1815. The Crimean War took place between 1854 and 1856, the American Civil was from 1861 to 1865 and the Boer War from 1899 to 1902. Queen Victoria reigned from 1837 to 1901 thus defining the true Victorian era. The British Engineers Prior to 1800 sources of motive power available were restricted to windmills, water wheels and low pressure steam with a maximum power of about 50 horse power. Early steam power pre 1700 was limited to pump- ing water. The development of the beam engine by Newcomen in 1712 led to a tier of pumps to lift 10 gal- lons of water through a height of 153 feet. The principle of these forms of steam power was condensing low pressure steam with a jet of cold water. Steam power was revolutionised by Watt in 1769 with a patent for a beam engine with a separate condenser evacuated by an air pump. In 1800, Trevithick developed a double acting high pressure steam engine for winding duties in Cornish mines and it was not until 1804 that the first successful railway locomotive pulled a load of 10 tons over a distance of 10 miles. It was not until 1831 that the principle of electromagnetic induction was demonstrated by Faraday. The era of major canal expansion in Britain was the second half of the eighteenth century and into the start of the nineteenth century, driven by the need to transport coal and other goods in greater quantities and more rapidly than had been possible previously. The key pioneering British Engineers involved in this were James Brindley (1716 – 1772), John Smeaton (1724 – 1792), John Rennie (1761 – 1821), William Jessop (1745 – 1814) and Thomas Telford (1757 – 1834). A major figure in the Manchester area, responsible for the Manchester Ship Canal, was Edward Leader Williams. Telford also had a major influence in surveying suitable routes for roads and arranging their construction for the London Holyhead route and throughout major parts of Scotland. Railways began to become competitive from about 1825 and there was a tremendous expansion of railway construction from the 1830s through to the end of the century. The railways became significantly faster than the canals in delivering goods and also provided convenient means for passenger transport. The key pioneers in this were George Stephenson (1781 – 1848), his son Robert Stephenson (1803 – 1859), Isambard Kingdom Brunel (1806 – 1859), Joseph Locke (1804 – 1860) and Thomas Brassey (1805 – 1870). Brassey was the contractor who undertook many of the actual construction projects to build the railways. Brunel became involved in the design and construction of very large ships in addition to his involvement in the railways. Canals, roads and railways all require the design and construction of bridges to provide suitable crossings. Thus all of the engineers involved in designing the transport routes had also to design bridges. Basic Principles Canals involve channels of water and hence have to consist of series of essentially level stretches. The sim- plest way to achieve this is for the canals to follow contours of equal height. Where the distances to achieve this become too long or are impracticable, it may be possible to construct tunnels or cuttings to carry the canal through a hill or mountain, or aqueducts to carry the canal over a valley. If changes in level are necessary, this is achieved though the use of locks in which the level within the lock is raised or lowered to match the water level for the stretches of canal each side of the lock. It should be noted that it is necessary to ar- range for a supply of water at different levels of a canal system to be able to top up water used in the locks and to make up for losses. Although railways can operate over changes in level, such changes have to be gradual and steep gradients must be avoided or the locomotive will not be able to pull its load up the slope and its driving wheels will slip. It is also necessary to avoid sharp bends and changes in direction must be gradual. In a similar way to canals, cuttings, tunnels and viaducts can be used to reduce the impact of changes in level. With railways, it is essential that the rails themselves are well supported and fixed in position to maintain their spacing for the wheels of the locomotive and carriages/wagons to run smoothly. The funding of the construction of both canals and railways was largely undertaken by private companies. The driving force for the companies was the perceived opportunity to make money from charging for the use of the completed asset. Each scheme required the approval of an Act of Parliament to permit the use of the land for the proposed purpose – this was often contentious. The money was usually raised by investment by shareholders – in the case of the railways £240 million. Most projects overran on both time and money! The actual construction of both canals and railways was undertaken by large groups of mobile construction workers, known as navvies. For the London – Birmingham railway for example, 20,000 men shifted 25 million cubic feet of earth in five years – enough to create a band of 3 ft width x 1 ft high around the earth’s equator. A full days work involved a target for each navvy of shifting 20 tons of earth. The navvies lived in temporary camps and had a reputation for getting drunk and fighting. Thomas Telford Thomas Telford was born in Eskdale, Scotland in 1757 as the son of a shepherd. He trained initially as a stonemason but in 1782 he moved to London seeking work and worked on Somerset House. In 1787 he became Surveyor of Public works for the County of Shropshire and became responsible for roads and canals in the County. He became fascinated with the potential use of iron in bridges. An early example was Build- was Bridge made of cast iron across the River Severn in 1796 (Figure 1). This bridge has been replaced twice since that time because of ground movement. One of Telford’s most striking iron structures was the Pontcysyllte Aqueduct carrying the Ellesmere/Llangollen Canal across the valley of the River Dee (Figure 2), built between 1795 and 1805 and still operating today, known as ‘The Ribbon in the Sky’. The canal is carried in iron troughs on 19 cast iron arches of 45 feet (13.4 metres) span, supported on brick piers at a height of up to 126 feet (38 metres) above the valley below. Telford showed his versatility in design of bridges with the Conwy and Menai suspension bridges, again both still in existence although now bypassed to accommodate the much increased numbers and weights of modern vehicles. Arch bridges have their main structural members in compression and hence cast iron was suitable for these purposes, but for the critical tension elements of suspension bridges Telford had to move to the more reliable wrought iron. The Menai Bridge was required to have a clearance height above the water of 100 feet to allow tall ships to pass beneath. Telford’s design involved support by 16 massive chains holding up a road length of 580 feet between the massive stone piers. Nothing approaching this scale had been built previously. The bridge opened in 1826 and was part of the Shrewsbury to Holyhead road scheme designed by Telford. After completing the Ellesmere canal, Telford moved back to Scotland where he completed the Caledonian Canal and was responsible for development of some 1920 km of major road networks. Telford was responsible for specifying a very high quality of road manufacture involving carefully graded layers of compacted stone of different sizes. This was more expensive that the alternative introduced by John Macadam which used crushed stone coated with tar and did not require the same thickness layers, but Telford’s roads gave excellent long lives. Whilst in Scotland Telford was responsible for the construction of many churches. He also made regular visits to Sweden where he was responsible for the Gotha canal. He returned to Shropshire in the final stages of his career where he was responsible for the Shropshire Union canal. Telford became one of the elder statesmen of the construction world and was elected the first President of the Institution of Civil Engineers from 1820 until his death in 1834. He became known as the ‘Colossus of Roads’ and was a truly great all round pioneer of engineering equally at home with roads, canals and bridges using stone or iron as materials. He was elected a Fellow of the Royal Society in 1827. Figure 1 Buildwas Bridge Figure 2 Pontcysyllte Aqueduct The Stephensons George Stephenson was born in 1781. He was an inventive practical man but had little basic education. He was responsible for development of improved miner’s safety lamps but became fascinated by steam engines and railways.

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