I received a few welcome gifts for Christmas 2025:
Colin Judge; The Locomotives, Railway and History 1916-1919 of the National Filling Factory No. 14, Hereford; Industrial Railway Society, Melton Mowbray, Leicestershire, 2025.
Anthony Burton; The Locomotive Pioneers: Early Steam Locomotive Development – 1801-1851; Pen and Sword, Barnsley, 2017.
Christian Wolmar; The Subterranean Railway: How the London Underground was Built and How it Changed the City Forever (2nd extended Edition); Atlantic Books, 2020. This edition includes a chapter on Crossrail.
Neil Parkhouse; British Railway History in Colour Volume 6: Cheltenham and the Cotswold Lines; Lightmoor Press, Lydney, Gloucestershire, 2025.
1. The National Filling Factory No. 14 at Rotherwas
I have an abiding interest in the railways of Hereford and so was delighted to receive Colin Judge’s book as a Christmas present.
Judge’s book focusses on an area to the Southeast of Hereford, surrounding Rotherwas House, which was to become an essential element of the British war effort. Initially, intended to be a reserve filling station, National Filling Factory No. 14 was quickly to become vital when on 1st October 1917, the factory at Morecambe was put out of action by an explosion and a major fire. Later, on 1st July 1918, an explosion at the Filling Factory at Chilwell killed 134 employees, leaving it only able to produce munitions at a much reduced level. No. 14 was critical to the supply of munitions.
The usage of shells during the conflict was frighteningly high, staggering! Judge tells us that during the Battle of the Somme 1,738,000 shells were used, and that at Passchendaele, over 5 million shells were fired. It is difficult to appreciate what those on the battlefield experienced. [1: p4]
This rate of usage demanded an unbelievable level of activity on the home front. 507 acres were purchased for the new factory around Rotherwas House. “The order was then given on the 30th May 1916 to commence the drawings and these were started on the 1st June 1916. The set of drawings for the Amatol section of the factory was finished and sent out to tender on the 12th of June. … Then the remaining drawings, of the Lyddite/Picric area were finished on the 15th of June and again dispatched to the various tenderers … construction [commenced as soon as] the final contractor was chosen.” [1: p15] John Mowlem & Co. Ltd won the contract on the basis of a guaranteed lump sum of £1,200,000 (approx £133,392,000 in 2025!).
Remarkably, in an incredible feat, 3,000 drawings covering the factory and an outpost at Credenhill (an ammunition storage facility) were produced in just a fortnight! All drawn by hand! Even more incredible when a significant design change occurred increasing the required output from the factory from 400 tons of Amatol and 200 tons of Lyddite per week. The new demand was for 700 tons of Amatol and 400 tons of Lyddite each week!
The contract for the construction was signed by both parties on 5th July 1916. Work progressed at speed and the first shell was being filled in the Lyddite area on 11th November 1916. The Amatol side of the factory filled its first shell on 22nd June 1917.
Judge tells us that Mowlem had to assemble the Amatol and Lyddite areas, a huge army ordnance depot (Rotherwas stores), barracks for the guards (alterations to Rotherwas House), hostel accommodation in Hereford for construction workers, stores and barracks at the Credenhill site (6 miles further from Hereford and on the Midland line from Hereford to Hay and Brecon). [1: p18]
The story of the works is copiously illustrated with contemporary plans and photographs and a modern diagrammatic representation of the internal railway system at the factory site. There were more than 27 miles of internal standard-gauge railways! [1: p16-17][5] In addition, the Picric/Lyddite area of the works was served by a significant network of 2ft-gauge lines. [1: p16]
In addition to covering the history of the site during World War 1, Judge describes the fleet of 2ft-gauge locomotives known to be used by John Mowlem &Co Ltd during construction of the site. These included: Kerr Stuart Wren Locomotives, KS2473, KS2474 and KS2477, all built in 1916; and Bagnall works number WB1740. Other locomotives may also have been used during construction: KS1047, KS1142, KS1144, KS 4017, KS 4018.
Judge provides drawings of the Kerr Stuart Wren Class of locomotives [1: p10 & 11] and details/photographs of the Bagnall Locomotive, works No. WB1740. [1: p11-14]
Judge provides notes on the locomotives used at Credenhill [1: p54-63] and at the Rotherwas Site. [1: p77-92] He also includes a chapter which is well-illustrated, focussing on the employees and the operation of the Rotherwas Site.
Chapters headings in Judge’s book are:
Chapter One: Brief History of the Proposed Area for the National Filling Factory No. 14, Hereford.
Chapter Two: Why did Britain need a new National Shell Filling Factory?
Chapter Three: Ministry of Munitions purchase of the land for the National Filling Factory No. 14, Hereford.
Chapter Four: John Mowlem Ltd – the Contractor and his Locomotives used on this site.
Chapter Five: Construction of the National Filling Factory No. 14, Hereford.
Chapter Six: The Great Western Railway, London & North Western Railway and Midland Railway’s involvement in the Factory’s Construction and Operation.
Chapter Seven: Credenhill – Army Ordnance Depot – the NFF Hereford’s Outpost
Chapter Nine: Basic Operations at the Hereford No. 14 Factory, Rotherwas.
Chapter Ten: Details of the Locomotives known to have operated on the internal railway at Hereford No. 14 (Rotherwas) Factory site.
He also includes as an Appendix, a short history of the site throughout the 20th century.
Rotherwas was revived as a Royal Ordnance Factory (Filling Factory No 4) with the onset of the Second World War in 1939, and filled large bombs and 15 inch (38 mm) shells for naval guns. [6]
References
Colin Judge; The Locomotives, Railway and History 1916-1919 of the National Filling Factory No. 14, Hereford; Industrial Railway Society, Melton Mowbray, Leicestershire, 2025.
Anthony Burton; The Locomotive Pioneers: Early Steam Locomotive Development – 1801-1851; Pen and Sword, Barnsley, 2017.
Christian Wolmar; The Subterranean Railway: How the London Underground was Built and How it Changed the City Forever (2nd extended Edition); Atlantic Books, 2020. This edition includes a chapter on Crossrail.
Neil Parkhouse; British Railway History in Colour Volume 6: Cheltenham and the Cotswold Lines; Lightmoor Press, Lydney, Gloucestershire, 2025.
Derived from the remains of microscopic fossilized sea or freshwater algaes, diatomite is a naturally occurring, versatile mineral used in an array of applications from cosmetics to filtration. [4] It was harvested by drag line from Loch Cuithir in the late 19th century and the first half of the 20th century.
“This unique form of silica has an elaborate honeycomb structure, peppered with thousands of tiny holes ranging from a few microns to submicron diameters. No other silica source, be it mined or artificially produced, presents such a structure. Some diatomite deposits are saltwater but most are from freshwater sources. … When ground, this profusion of shapes results in an extremely low-density powder known as ‘diatomaceous earth’ (DE) which has excellent absorption properties that are highly prized for filtration, agriculture, paints, plastics, cosmetics, and pharmaceuticals application.” [4]
Diatomite was also used in the production of dynamite. [2][3]
Possibly as early as 1885 [1] but certainly by 1889, [2][3] work was underway at this site. A 2ft [2][3] or 2ft 6in [1] gauge tramway was being constructed in 1889 from the drag-line at Loch Cuithir to Lealt. The tramway followed the River Lealt down to its mouth at Invertote. When first opened the line was worked by gravity and manpower. Apparently, later in the life of the line a small steam locomotive was in use. [2][3]
At the “Western end of the line … at Loch Cuithir, … diatomite – known locally as Cailc (Scottish Gaelic for chalk) – was taken out from the loch bed and dried on wire nets. The seaward terminus had warehouses on the cliff-top at Invertote. At the base of the cliff was a factory where the diatomite was kiln dried, ground and calcined. [A] line … extended from the factory onto a pier into the Sound of Raasay.” [2][3]
Diatomite was also gotten from Loch Valerain and transported by aerial ropeway to Staffin Bay and on along the coast to Invertote Apparently, “during its existence, the Skye Diatomite Company extracted 2000 tons of diatomite. … From Invertote, the diatomite was transferred by skiff, onto puffer boats, waiting in the bay, and shipped across to the mainland. The diatomite was turned into kieselguhr which was mixed with nitroglycerine by Nobel Industries, at Ardeer, to make dynamite.” [2][3]
Stornoway Gazette described the operation as follows:
“Over the years, the mine saw periods of inactivity, but when up and running operations made use of the large industrial works at the area – a large factory building, a railway with embankment cuttings, and a rolling stock traversing three miles of landscape, including an aerial ropeway. The light railway was used to transport the Loch Culthir Diatomite to the shores at Invertote for a final drying and grinding, and a large building containing a furnace, grinding machine and storage space was constructed there for this purpose. Such modernised business works were quite remarkable for this part of the world at the time. In those days there was no road between Staffin and Portree, so a puffer boat would anchor in the bay at Lealt, and local skiffs were used to transport the finished Diatomite from shore to boat, ready for shipping to the mainland. There were around 40 to 50 people steadily employed at Lealt, yet on days that the boat came in this total rose to as many as 80 workers.” [7]
“Perhaps one of the most intriguing aspects of the mine’s history comes from the ownership of the drying factory at Invertote by Germans. Although closed during the period of the Great War, surprisingly the now enemy foreign residents were allowed to stay on. Shortly afterwards a rumour began to circulate that the area was haunted and that the ghost of a recent tragic death at the Lealt falls had appeared at the factory. As the local story goes, (the rumour was actually started by the Germans) with the intent of keeping locals away. It turned out that the resident Germans were spies and that, almost unbelievable to the community, the area was being used as a German base with submarines surfacing in the sea bay!” [7]
“Moving on, the year 1950 saw the next development in the mining of Diatomite from Loch Cuithir. As the loch was one and a half miles up the moor, through peat bogs and rivers, the Department of Agriculture and Fisheries for Scotland (DAFS) decided that a road should be built, with the intention of extracting the Diatomite by digger, and then taking it to the Lealt road end above Invertote. The road took around a year and a half to build, during which the mine was put out of operation. Yet, when production started again, the new method of extraction did not reach the high standard of quality which was achieved when extracted manually by spades. The mechanical extraction resulted in the Diatomite being less pure, and full of unwanted dirt. Drying the substance is, in fact, the problem of the process, for it is obvious that in a damp climate like Skye, the diatomite does not lose its moisture quickly. The problems which began after the construction of the 1950s road were further highlighted and compounded six years later. A new factory was built at Uig (the site where the Cal Mac offices are now situated), far from the mining site at Loch Cuithir, and it may be said that this move was the ruining of the entire Diatomite industry upon Skye. As Diatomite was no longer dried at Invertote it now had to be transported by road, wet, for the much-needed drying process to Uig, 23 miles away. A vehicle may have left Loch Cuithir carrying five tonnes of Diatomite, yet only producing one tonne of the finished product after drying had taken place – a finished product which was also not as pure as it ought to be for the specialised work it had to do in various products. A lot of money was wasted on travelling, and within the factory itself, inefficiency was also present, with machinery often breaking down due to the damp state of the Diatomite. Outside the factory, the scenic communities of Trotternish also began to suffer. When the factory was working, it poured out a fine white dust which covered every house in the area. Grass became chalky in colour and after dry spells in the weather, the road-sides from Staffin to Uig would turn white with Diatomite – Uig was constantly under a cloud of dust. With complaints of insubstantial profits and bad management, the factory was finally closed to production for the last time in 1960. Yet, although the Diatomite mining industry on Skye came to an abrupt ending, it was still regarded by many locals as a blessing at the time. Following from World War One, the industrial works provided employment for many returning men who could not find work elsewhere in the island. And at peak production, around 1955/56, 50 to 60 men were paid good wages to work at the factory.” [7]
Bell & Harris tell us that “Loch Cuithir is located upon landslipped material, which overlies Upper Jurassic strata. Only parts of these diatomite workings remain. Some of the brick buildings, together with the line of the tramway used to transport the diatomite to the coast, are still obvious. The diatomite occurred as a 3–6m-thick horizon below a 1m covering of peat. The loch had an original area of 60 hectares (24 acres) and was drained in order to extract the diatomite. Ditches, around the perimeter of the loch, were excavated and the water was drained through a man-made outlet at the northern end of the loch, thus allowing removal of the peat and extraction of the diatomite. East of the drainage outlet are spoil-heaps, mostly of plateau lava boulders, presumably removed from the workings during excavation. The diatomite from this deposit was very pure, with little or no interlayered silt or mud. Macadam (1920) notes that the calcined (heat treated) diatomite contains over 96% [Silicon Dioxide](reported in Anderson and Dunham 1966), whilst Strahan et al. (1917) gave a value of 98.78%. According to Macadam (1920), the absorptive value of the material from Loch Cuithir was over 3.56 (a good diatomite would have an absorptive value in excess of 4.0).“
Some excellent photographs of the derelict factory at Invertote can be seen here. [8]
The Route of the Tramway/Railway
From Loch Cuithir, the railway ran in a Southeasterly direction over boggy ground. Minimal earthworks were undertaken placing the railway at a level just above surrounding ground.
The Canmore National Record of the Historic Environment profiles these notes:
“One of the greatest causes of interest in Skye Diatomite was its potential use as a substitute for Kieselghur by Alfred Nobel in the production of Dynamite in Nobel’s new Scottish factory at Ardeer in Ayrshire during the 1880s. Nobel eventually found a better source of material, but the Extraction of Diatomite nevertheless began in Skye at Loch Cuithir in 1886. The Diatomite was transported by tramway to be processed at Invertote, production continuing until 1913. The industry was briefly revived between 1950 and 1961, using road transport.” [13]
“The principal remains of the Invertote works are a large, rubble-built, rectangular-plan roofless building (NG5201 6049). It has been entirely gutted, but fragmentary remains include a large cast-iron flywheel from a steam engine, and a cast-iron wall-mounted bearing box. The other surviving structure is a kiln (NG5201 6052), comprising a lower chanber or firebox built from Scottish firebricks (produced at the Star Works, Glenboig, Lanarkshire, and Etna Works, Armadale, West Lothian), onto which has been constructed a circular-section fireclay-brick column encased by an outer layer of sheet steel. The exact functions of the processing building and the kiln are uncertain, but it is likely that the latter was used for drying purposes.” [13]
Roger Farnworth 