The historic significance of the UK railways and the role played by George and Robert Stephenson in their development cannot be overstated. Granted, the first steam locomotive was the brainchild and creation of the Cornishman, Richard Trevithick (1771-1833), but the midwife at the birth of the railways was George Stephenson (1781-1848).
Born in Northumberland, George Stephenson first worked as a farm hand and then as a fireman and brakesman at coal pits on Tyneside. After spells at Willington Quay, Killingworth, Montrose and Killingworth again – where in 1811 at the new High Pit he modified an atmospheric pumping engine so that it became able to keep the pit dry – he was placed in charge of all the machinery in the collieries of the Grand Allies (Earl of Strathmore, Sir Thomas Liddell and Stuart Wortley). He left their employment in 1813 to become a civil engineer, although his work until 1821 was confined to pumping engines and the improvement of coal handling at collieries. In that year, he was engaged by the Stockton & Darlington Railway Committee; which opened to railway traffic in 1825 – the rest is history.
Robert Stephenson (1803-1859) lived largely in his father’s shadow during his formative years, assisting on the surveys for a wagonway at Killingworth, the Stockton & Darlington Railway; although he was able to spread his wings when, at the tender age of 19, he was made managing partner of Robert Stephenson & Co, located in Newcastle. This Company had been set up for the manufacture of steam locomotives and equipment for the rapidly expanding railway industry.
However a year, almost to the day, later he departed for a three-year stint (1824-1827) mining in Colombia. On his return he spent the next six years pursuing his career as civil engineer and factory manager. He was heavily involved in the design and construction of the first inter-city Liverpool & Manchester Railway, the Canterbury & Whitstable Railway, the Leicester & Swannington Railway, and many others. On the mechanical side, he played a leading part in improving the dynamic and thermodynamic performance of the clumsy colliery locomotives to transform them into engines more suited to main-line services and culminated in the manufacture of the Rocket – the clear winner of the Rainhill Trials. In 1830 he undertook an urgent preliminary survey of the 180km route from London to Birmingham and subsequently carried out a line survey with levels, together with a detailed examination of the most difficult parts of the line including Kilsby Ridge. Following an unsuccessful parliamentary bill in 1832 and a successful one in 1833, Robert Stephenson was appointed engineer-in-chief of the London & Birmingham Railway in September of that year, still only 29 years old.
Railways changed the face of the world. From today’s perspective it is difficult to imagine their impact. From time immemorial the horse had determined the speed of travel, to perhaps 15km/hr for the best stage/mail coach systems. Railways changed all that. By 1854 rail travel had reduced journey times to 25-35% of the corresponding travel times on coaches in 1836.
The coming of the combustion engine at the close of the 19th century provided individuals with their own means of transport to match the journey times by rail, while commercial aeroplanes achieve speeds some 3 times or so more than the fastest rail services. Seen in this light the contributions of the Stephensons, father and son, to mankind ‘s evolution is enormous.
The Kilsby Tunnel
The construction of the 2193m long Kilsby tunnel proved to be the most difficult and time consuming operation in the building of the London & Birmingham Railway. For three long years tunnellers strove to subdue the quicksands present at the southeastern end of the tunnel and the resulting delays postponed the opening of the completed line by about eight months.
At the time of its conception Kilsby was the longest railway tunnel thus far contemplated, with opponents of railways and harbingers of woe predicting suffocation for passengers foolish enough to travel through it. Because of these doubts Robert Stephenson planned two huge ventilation shafts both 18.3m in diameter and over 30m deep and topped with castellated towers. In addition to these ventilation shafts it was proposed initially to sink eight construction shafts but this was later to be doubled to 16 in order to speed completion; in the event following the encounter with the quicksand a total of 25 shafts were sunk.
The tunnel passes through the Northamptonshire uplands at a maximum depth to invert of a little over 40m and was 8.3m high and 7.3m wide internally. Originally a 457mm thick lining was proposed, but this was later increased to 686mm; an invert 356mm thick is shown on the design drawings, but this may well have been increased to 457mm in the final construction; it would be a reasonable inference that these modifications were the result of the ground pressures experienced during the construction of the Primrose Hill tunnel through London clay. It would also be reasonable to assume that the temporary timber support used in the Tunnel was similar to that at Primrose Hill, which from the limited information available appears to be very similar to that described in Simms (1896).
Two preliminary site investigation boreholes 15m deep, near the ends of the proposed tunnel, revealed hard clays of the Middle Lias formation. After the line of the tunnel had been finalised four trial shafts were sunk in the positions and to the depths shown on Figure 2. They showed a capping of up to 8m of Glacial Drift boulder clay and gravel – overlying the Lias clays with occasional relatively thin layers of limestone. Considerable amounts of water issued from the deeper rock layers and this proved to be troublesome during construction. However, as can be seen on the Figure the trial shafts just missed the sand-filled buried valley, which proved to be the seat of the problems.
A shorter tunnel could have been constructed about a kilometer farther east but previous borings there in 1811 for the Grand Union Canal had shown quicksand and their engineer, Benjamin Bean, had adopted an alignment further to the east for the canal tunnel built in 1812-14 without much difficulty. For the same reason Stephenson chose the Kilsby alignment as an alternative route for the railway. It was, therefore, unfortunate that the presence of quicksand at Kilsby had not been discovered by the time the tunnel contract was let to Joseph Nowell and Sons in May 1835.
The contractor began by sinking construction shafts the first four of which, in the middle and north of the ridge, proceeded without difficulty but a shaft about 500m from the southern end encountered sand. The groundwater level was 8m below the surface and work had to stop at a depth of 11m as the liquefied sand simply boiled up into the shaft as fast as it could be removed. Six investigation boreholes showed that there was a major construction problem, as the tunnel would have to pass through some 350m of the quicksand, which at its lowest point was some 2m below rail level. Frank Foster, the district engineer, had boreholes sunk along another alignment but this was no better. It had to be accepted that work could proceed through the sand only after it had been drained.
Stephenson, probably forseeing the problems and delays that would result from the considerable depth of groundwater involved, advised in mid-October 1835 the purchase of two large pumping engines but delays in delivery frustrated immediate actioning of this plan. Just before Christmas 1835 following discussions with the contractor and the assistant engineers it was decided to use a heading to drain the sand. Work began on driving this into the south-eastern side of the hill parallel to the line of the tunnel and by the end of December had progressed halfway towards the sand.
Unfortunately, a sudden inrush of sand swept into the heading blocking it completely for a length of 80m. Although the heading was reopened and extended it had to be abandoned in February 1836.
The situation was also exacerbated by Joseph Nowell’s illness and his death on 12 January 1836 and by his sons being obliged subsequently to withdraw from the contract as they lacked the necessary funds to continue once their father’s will had been proved. Henceforward the works at Kilsby tunnel were carried out by direct labour, supervised by the assistant engineer Charles Lean directly responsible to Stephenson himself.
Unsurprisingly, the Directors were alarmed at the situation and dispatched Captain Moorsom to Kilsby to interrogate Robert Stephenson and to suggest to him that the help of other engineers be obtained: James Cropper a long standing antagonist of the Stephensons initiated the move by implying that the difficulties were the inevitable consequence of employing so young and inexperienced an engineer-in-chief. However, Moorsom was so impressed by Stephenson’s confidence and the clarity of his plans for dealing with the difficulties that he convinced the Directors on his return to Birmingham to have complete trust in him; as a result in March 1836 Stephenson’s recommendations involving the construction of a railway over the ridge and extra shafts to speed up the draining and tunnelling by increasing the number of working faces were accepted.
In tandem with the above, the first 20hp (14.9kW) pumping engine had been erected in December-January and sinking of the 3.6m diameter pump shaft began at the beginning of February. As the groundwater was lowered, so the shaft was slowly deepened and lined with wooden ‘tubbing’. Reduced to 2.7m in its lower half, this shaft reached the bottom of the sand close to rail level in September. The second pumping engine began work in July and its shaft reached bottom in October; cross headings were then driven from the pumping shafts, which acted as sumps, towards the proposed positions of the working shafts to enable these to be driven in the dry.
Sinking of the working shafts began in November 1836 after nearly twelve months of pumping, during which the groundwater level on the line of the tunnel had been lowered by 18m. Lean’s regular reports show periods of steadily lowering watertable followed by fresh influxes of water. The only solution was additional pumping and shafts and the purchase of more pumping engines all of which increased costs. In the end it took thirteen pumping engines discharging at a rate of 136lt/sec to finally stabilise the quicksand and enable the tunnel to be constructed through it.
A drawing by Bourne in 1839 (see p25), shows the No 2 engine house and the cranks operating two pumps in a shaft. Also shown is the headgear of a horse-gin at a nearby working shaft and No 1 engine house in the background.
Pumping had to continue throughout construction to maintain the lowered groundwater levels, enabling tunnelling to proceed with great care from the working shafts. Simultaneously work was being carried out in the Lias clay from the other shafts.
The state of construction at the beginning of May 1837 is shown on Figure 1 when progress was well behind the original schedule; the entire tunnel was completed in June 1838. At any one time upwards of 1300 men and 200 horses had been employed on the construction of Kilsby Tunnel; some 25M bricks had been needed to complete the tunnel lining and the two 18m diameter ventilations shafts. But it had all cost in excess of £320,000: this compares with a contract price of £98,988 and a parliamentary estimate some years earlier of £84,815. Unforeseen ground conditions were always expensive!
Kilsby Tunnel was significant in the history of civil engineering for two reasons. It represented the first major application of groundwater lowering by pumping. Secondly Stephenson was the first to observe and explain in clear qualitative terms the flow of groundwater through sand to a source of pumping: it would be 1863, another 17 years, before Dupuit developed the mathematical analysis of that situation, which is now standard issue in textbooks on Soil Mechanics.
Bicentenary of the birth of Robert Stephenson
The triumph of the Rocket at the Rainhill Trials in 1829 and the successful completion of the London & Birmingham Railway in 1838 marked the end of the beginning of the making of Robert Stephenson’s reputation. He had set up his business as a consulting engineer in 1835 and by the end of that decade was acknowledged as one of the UK’s leading engineers: in the 1840’s he was to become the leading railway and bridge engineer in the UK and perhaps the world.
Apart from the London & Birmingham Railway highlights of Stephenson’s career included the Chester and Holyhead, the Newcastle and the Berwick and North Midlands Railways and the bridges at Conwy, the Menai Straits (Britannia Bridge), Newcastle-upon-Tyne (High Level Bridge) and Berwick-on-Tweed (Royal Border Bridge). Overseas his work included railways in Belgium, Denmark, France, Italy, Norway, Spain, Sweden and Switzerland and further afield in Canada, Egypt and India: his most notable bridge was the Victoria Bridge across the St Lawrence River near Montreal. But not all his endeavours were blessed with success and the collapse with a train on it of the trussed cast-iron beam bridge over the river Dee at Chester in 1847 distressed him greatly, and he clearly got it wrong when he said engineering difficulties would make a Suez Canal impossible.
Stephenson was first elected Member of Parliament for Whitby in 1847 and elected a Fellow of the Royal Society in 1849: he was President of the Institution of Mechanical Engineers from 1849-1853 and of the Institution of Civil Engineers in 1856-57. Like his father before him he declined to accept a knighthood.
In later life he developed a passion for sailing and his yacht Titania was the only English boat to accept the challenge to compete against the racing yacht America, in what was to become the “Americas Cup” races.
Stephenson died of liver failure on 12 October 1859 and has the distinction of being one of only two engineers – the other being Thomas Telford – to be buried at Westminster Abbey.
Related Files
Fig 1 – Progress of tunnel works at Kilsby on 1 May 1837 (courtesy of the ICE)
Fig 2 – Longitudinal section of the Kilsby tunnel (source: Prof. AW Skempton)
