"Dynasty of Engineers - The Stevensons and the Bell Rock"
Published by the Northern Lighthouse Heritage Trust (2011).
Now available (or can be ordered from) from Whittles Publishing or any good bookseller.

THIS PAGE is an abridged version of a Paper given at the Fifth International Early Railways Conference at Caernarfon on 9th June 2012. My special thanks to Prof. Paxton for allowing the use of this hitherto unpublished insight into an early and important cast-iron railway.

The Bell Rock Railways

by Prof. Roland Paxton

Introduction

IN 1806 AN ACT OF PARLIAMENT authorised the erection of the Bell Rock Lighthouse. It is located within the tidal range of the sea eleven miles out to sea from Arbroath, Scotland, on a hard sandstone reef several hundred yards long, submerged up to 15 ft at high water.

The east coast of Scotland from Edinburgh to Aberdeen showing the location of the lighthouse.

From 1807-11 this 118 ft tall lighthouse was built in stone under the overall design and supervision of the eminent civil engineer John Rennie (1781-1821) as “Chief Engineer” and Robert Stevenson (1772-1850) as resident engineer (from 1808-42 Engineer to the Northern Lighthouse Board and on the lighthouse's completion, founder of the remarkable Stevenson dynasty of engineers (1811-1952)).

An outline of the railways on the Bell Rock - approx. 800 yards in length (731½m.).
The dotted parts of it were removed after the lighthouse was completed [Ed.]

To achieve construction at this hazardous location in four summer working seasons a narrow gauge cast iron railway “about 800 ft long altogether” was built connecting the site of the lighthouse with wharves at the rock edge. This enabled dressed stones from Arbroath Work-yard weighing up to 1½ tons to be transported across the rugged rock surface.

The paper describes and investigates from contemporary records, and the site inspection, the design, manufacture, erection, operation, innovation, attribution and influence of this unique railway which contributed essentially to the construction of one of “Seven Wonders of the Industrial World”.

The idea of using an elevated railway up to 6 feet above the rock surface, from timber wharves to the south (Pitmilly), the north-east (Duff's) and an another occasional landing and siding to the north was Stevenson's. He was the driving force behind the project for a stone lighthouse first proposed in 1800 and developed in 1807. Stevenson determined the railway's level and location, probably in consultation with his clerk of works and draughtsman, David Logan (1786-1834), who in effect acted as assistant resident engineer.

Research for this paper has revealed that the detailed design of the railway and its associated cranes under Stevenson, was essentially the work of foreman journeyman carpenter and millwright, Frances Watt. But, as this function was not specifically attributed to him in Stevenson's publications in time it was generally accredited to Stevenson himself.

Watt's working sketches and drawings for the railway probably no longer exist but a near contemporary engraving published by Stevenson does, to which explanatory details have been added. This shows Watt's design, except for the side braces which were added about a decade after he had left Stevenson's employment. The gauge was nominally 2 ft 6 in and the plate-rail upstand measures uniformly 1¾ in tall on site.

These three diagrams (above and below) of the Bell Rock Railway (track and waggon) are taken from Stevenson's "Account . . . " of 1824.

Watt was engaged by Stevenson in February 1807. By May 1807, prior to the temporary accommodation at Arbroath Work-yard being ready, he was working on details of the railway and cranes, probably at the Greenside Works, Edinburgh, a flourishing private lamp manufactory, in which Stevenson was a junior partner with his step-father and father-in-law Thomas Smith, from 1787-1808 part-time Engineer to the newly formed Northern Lighthouse Board.

On 8 January 1808 with a view to making a start on building the lighthouse in the summer, Stevenson instructed Watt to come from Arbroath to see him in Edinburgh as soon as he had finished “a proper draft of the crane, of the rock and railway”. Rennie was then pressing Stevenson “to see a sketch of what was proposed before it was done”. By the end of the month Stevenson was able to inform him that “the railways were partly fixed upon and modelled”.

A finely executed model showing building operations at the Bell Rock Lighthouse was made for Stevenson in c.1822, probably by James Slight (1785-1854). Slight later became a civil and agricultural engineer who also modelled structures and machinery as a promotional or design aid. Stevenson had first employed him at the Bell Rock works from 1808 and later on the strengthening of part of the railways by 1819.

The total cost of the ironwork for the railway amounted to £1002, of which £669 was paid to the Shotts Iron Company for “cast metal branders, rail road castings, mountings for waggon triangles and sundries”.

Erection and operation 1808-10

The Shotts-made ironwork for the railway had been delivered to Arbroath by early May 1808 when intense activity on the erection of the railway was under way for up to about three hours at each low water, tides and weather permitting, the men then having to travel by boat to and from their ship accommodation. This work included making seats and hand-boring the holes for the batts and screw-bolts to secure the feet of the cast iron supports.

Despite a Herculean effort the railway was not ready by 10 July 1808 when the foundation stone of the lighthouse was laid, or before the first entire course of 123 stones was completed on 12 August. These stones had to be placed through the sea from above at high water, before final positioning and fixing after the tide had receded, a difficult and dangerous operation.

The railway eventually began to operate towards the end of August, but only on the eastern (northern) reach from Duff's wharf, when it carried the second entire course of 136 stones weighing 152 tons, including some of about 1½ tons. By mid-September, when work stopped for the season, courses 1-5 (of 90) had been laid. Notwithstanding this progress the necessity of bringing into commission the western (southern) reach for greater convenience of operation was much felt.

The railway suffered minor damage in the winter gales although this was soon remedied. By 22 May 1809 great exertions were being made on laying the circular track around the tower. Typically a ten-man squad of millwrights, joiners and smiths were engaged on this work under Watt's direction. This number increased to twenty-four at periods from August to November when the temporary beacon barrack alongside the lighthouse became habitable making more time available for “extending and completing the railways leading to the western creek”.

Rennie inspected this work in progress on 24 September 1809. Although appreciating that the Stevenson initiative of the additional western (southern) railway reach would facilitate construction at different states of wind and the tide he thought it might not warrant the extra ”heavy expense”. Nevertheless he concurred with this measure in the best tradition of the chief engineer-at-a-distance/resident engineer relationship as practised by Smeaton, Telford and others.

Part of "Taylor's Track" and "Watt's Reach" in July 1810 looking east. Railway up to 6 ft. above the rock with its supports bolted to timber baulks below about 4 ft. [Note the ship in the background - the only known image of the schooner "Sir Joseph Banks" - Ed.] Copyright NLS

Even with the extended working time it was not until 17 June 1810 that the western (southern) reach became fully operational from Pitmilly wharf serviced by Watt's remarkable jib-crane with its optional mechanical advantage of either 20:1 or 98:1. Completion of this reach “had involved an immense effort in boring the rock, inserting iron-batts and operations, accessible only at the lowest tides . . . . Mr Watt and his squad had embraced every opportunity day and night – for this work was to the last carried out by torch light”. During the next eleven weeks the most intense period of activity on the project then took place resulting in completion of the tower masonry by 2 September 1810. Following finishing work the light became operational on 1 February 1811.

The total cost of the railway was about £2400 (excluding cranes) of which the labour element was about £1000 (excluding payments to the engineers). Watt received £436 from March 1807 – October 1810, of which about one third can be considered attributable to the railway. Basically he received 7s per day. Other rates ranged from 2s 2d per day for labourers to 3s 6d per day for mill-wrights.

A general view of the works as at 1810. It shows, not only the full extent of the railways, but also the use of the cranes (jib cranes at either end of the railways and the balance crane at the top of the tower).
Photo: Northern Lighthouse Heritage Trust

1819 strengthening of railway for lighthouse access

The railway had successfully enabled completion of the tower by 1810 but any hopes that it might have served permanently were soon dispelled. Stevenson found after a storm on 30 October 1810 that “the railways (were) much broken up on the eastern reach and circular track round the building; while the western railways, extending to upwards of 290 feet has also materially suffered. In several places it had got an inclination to one side, by the force of N.E. Sea which came sweeping round the rock, and it was evident that it could not withstand the gales of winter. The Norway logs, on which these railways were supported, had not only been much reduced in weight by the ravages of the sea-worm (limnoria terebrans) but from this cause also, the rails had got a tremulous motion in heavy seas which had shaken loose several of the bolts”.

These photographs were taken during work on the lighthouse in the 1980s - probably when preparing for automation. Top - shows the somewhat chaotic state of the railway supports over 175 years of use and successive repairs. Bottom - taken from the top of the lighthouse showing the existing railway and helipad. Photos: Eddie Dishon.

Although repaired without too much difficulty, the railway afterwards was repeatedly damaged in storms. This required strengthening to be undertaken from 1815-19 on “Watt's Reach” and making a realignment, known as “Slight's Reach,” as a permanent access to the lighthouse about 180 ft long overall, only about a quarter of the original railway length. The work involved provision of the side braces previously mentioned, the use of strong batt fastenings, and plastering over the feet of the supports with roman cement to inhibit oxidation. It cost about £1100”.

Conclusion

This hazardous-to-construct elevated plate-way, empirically achieved against the ravages of the sea by exceptional courage, determination and skill, made an essential contribution to one of greatest the engineering feats in modern history.

The project was all the more remarkable in being effected before the development of such improvements as portable steam-powered equipment, patent timber preservatives, artificial cements and, not least, “strength-of-materials” design. The latter did not begin to develop in this context until 1844 when a storm wave force equivalent to a pressure of 2013 lb per sq ft was first measures at Bell Rock. This is indicative of the order of hostility to which the railway structure was subjected occasionally (and Rennie's prudence in adopting a pronounced curvature for the lighthouse base).

The railway was designed in detail and erected by Watt to the concept of and under the direction of Stevenson with the approval of Rennie. The 1815-19 strengthening of part was carried out by Slight under Stevenson's direction. The total cost was about £3500, equivalent to at least £2 million now.

The railway's success was the catalyst to Stevenson becoming by 1820 the “great authority” on Scottish pre-steam locomotive railways. His many projects, although mainly unexecuted, showed foresight being more or less on the lines of the eventual network. A report on one in 1818 also influenced the early introduction of the malleable iron edge rail, a vital break-through in railway development. He advocated the measure “as likely to be attended with the most important advantages to the railway system”, a contention that encouraged Birkinshaw to develop and manufacture his epoch-making wrought iron edge rail in 15 ft lengths from 1820.

Although the railway was not identically replicated elsewhere, its concept had a lasting influence for at least three-quarters of a century in that railways were advantageously adopted in the construction of other isolated lighthouses including Skerryvore (1839-42), Dhu Heartach and its shore station Erraid (1869-72), and Ailsa Craig (1885).

Other types of project for which the railway concept was adopted to facilitate construction included Hutcheson Bridge, Glasgow (1831-34), designed by Stevenson where wrought iron under-bellied edge rails were used. This application was promoted nationally through Weale's Bridges.

The concept was also adapted on harbour works, for example at Wick Breakwater where stone bought by railway from local quarries was uplifted by jennies on travelling frames moving on railways to open staging through which it was lowered into position (1868). Other examples of both practices are illustrated in the plates to Vernon-Harcourt's Harbours and Docks.

Finally, the surviving railway at the rock, although mainly a painstaking replica dating from 1917, is nevertheless a wonderfully evocative unique exemplification of pre-1820 narrow-gauge plate-way technology and the longevity of cast iron in a hostile environment.

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Appendix – Francis Watt (1778-1823?), inventor and artisan

Little is known about Francis Watt which is the reason for this appendix. David Logan, Bell Rock Lighthouse clerk of works (later Chief Engineers of the Clyde Navigation) considered that Watt's applications of mechanical power at the Bell Rock Lighthouse were “highly unique and valuable” a statement borne out by this paper.

Logan felt so strongly about this and wishing to see that Watt received his due credit, which he did not feel had been sufficiently acknowledged by Stevenson, he took the trouble of preparing details of Watt's innovative cranes developed during the Bell Rock works for publication. These comprised anonymous articles on Watt's jib-crane and arguably his most significant invention, the world's first iron counter-balance tower crane used for erecting the upper part of the lighthouse above the range of the jib-cranes.

Logan's articles were first published in the little-known Caledonian Journal and then reprinted nationally as front-page features in the Mechanics Magazine. The jib-crane article was also reprinted in several editions of Jamieson's Dictionary of Mechanical Science.

Watt was baptised on 18 July 1778 at Greenburn, Newhills, Aberdeen. That he is this Francis Watt in the Old Parish Records is attributed from Logan's information that he was born at or near Aberdeen, confirmed by a letter from Watt to Stevenson dated 8 September 1810 written from “Greenburn by Aberdeen”. Nothing is known of Watt's education which was probably gained at a local school before entering the carpentry trade.

According to Logan, Watt worked as a journeyman carpenter on Fochabers Bridge over the River Spey (erected 1801-1805) and then at the Caledonian Canal works, probably from c. 1805 to 1807, under the overall direction of leading civil engineers Telford and Jessop.

Watt was 29 years old when he started work on the Bell Rock Lighthouse project in March 1807 at two guineas a week. He continued in this employment until 31 October 1810, over which period he was paid £436 (about £10 per month). A premium was paid for work on the rock and his greatest monthly payment of just over £20 was in June 1810. He seems to have had a good working relationship with Stevenson who makes only the broad passing acknowledgement in his magnum opus that he “had profited by (Watt's) ingenuity in reference to machinery” and his “zeal and intrepidity in erecting the beacon and railways”.

In September 1810 Watt wrote to Stevenson that he was looking for work and hoped “to get a job soon”. Soon afterwards he went to London, it is said in the service of Rennie, possibly working on the Waterloo Bridge.

On 26 November 1812 Stevenson took trouble to ensure that Watt received a copy of the separate printing of his Account of the Bell Rock Lighthouse by sending it to London in the hands of “Capt. Brown who occasionally tells me of your welfare and who will know your address in London“.

Watt was probably still alive in November 1820 as in a letter then Logan makes mention of obtaining Watt's permission to publish details of his inventions. Nothing seems to be known of Watt's work or life in London, but because of his inventive propensity he may have been the Francis Watt awarded the Silver Vulcan Medal of the Society of arts and ten guineas, for his invention of a screw-wrench for loosening and securing square-headed screw-bolts, his model of which was deemed of sufficient merit to be placed in the Society's repository.

By 21 April 1823 this Francis Watt was very ill, presumably living in Lambeth, London, and died short after, on the day that his screw-wrench invention was brought before the Society's Committee.

A slightly fuller account of Watt which seems to be largely based on Logan's information was published by Robert Mudie, a miscellaneous writer who espoused the cause of promoting engineering talent. Mudie refers to Watt as “a contriver in cases of emergency” and as “having great inventive talent” but also as “a frequenter of alehouses . . . (in which) matter he was allowed to have his way only to be always ready at a call”.