The Imperial Smelting Corporation’s facility in Avonmouth operated its own industrial railway system of both standard and narrow (2ft) gauges.

The ISC maintained its own fleet of locomotives, one of which, No.2, was of a similar design to ‘Portbury’ and since 1972 has been preserved on the Avon Valley Railway, where it is in the process of being restored.

ISCL No.1 – Hudswell Clarke No.1246 of 1916. Ordered for Ministry of Munitions, Explosives Dept. (dp: H.M. Factory No. 1, Avonmouth). Became ISCL property 1924.
0-6-0T of same type as Manchester Ship Canal locos.
Scrapped in 1960

ISCL No.2 – Avonside No.1798 of 1918
0-6-0ST of same design as ‘Portbury’ but with extended bunker and circular rear spectacle plates.
Originally Ministry of Munitions, became ISCL property in 1924.
Gordon Edgar captured these photograph of this loco in 1970. No.2 was still in use as a standby locomotive. John Donnelly took the two photos of No.2 in steam.

ISCL No.3 – Hudswell Clarke 1815 of 1948
0-6-0T
Possibly an outside cylinder type similar to ‘Nunlow’ on the KWVR although I have no photos to verify this.
Scrapped December 1960

ISCL No.4 – Wolverhampton-built ex-GWR pannier tank 657 of 1898 (ex-BR 2053)
Bought September 1954
Scrapped March 1961

Ex-GWR 2053 class No.657 crosses Kingsweston Lane in 1959. Photo taken by M. E. J. Deane, from the collection of the late Mark B. Warburton, published in Steam Around Bristol (written by Gerry Nichols for Crecy). With thanks to Gerry for providing the correct information.
Purchase a copy of Steam Around Bristol here (link to Waterstones).

Two Sentinel diesel hydraulic locos were purchased new (replacing Nos. 1/3/4 with No.2 being kept on as spare engine) followed by a third bought second-hand.

No.5 – Sentinel 10005 of 1959
4wDH
Bought new

No.6 – Sentinel 10048 of 1960
4wDH
Bought new

No.7 – Sentinel 10023 of 1960
4wDH
Bought from Swansea Vale Works in 1974

Previous locomotives owned by Ministry of Munitions Avonmouth, then National Smelting (which became Imperial Smelting) included:

Standard Gauge

No.1 ‘English Crown’ – Peckett 1545 of 1919
0-4-0ST
ex Port Tennant Works, Glamorgan
Later sold to New Cheshire Salt Works.

No.2 ‘Kingsley’ – Hunslet 714 of 1900
2-4-2T built for the Bideford, Westward Ho! and Appledore Railway and requisitioned for war work along with its two sister engines in 1917. The BWH&AR was not rail-connected to the national network so temporary tracks were laid across the road bridge to get the locos out. They did not return after the war and so the railway closed. Sister locos ‘Grenville’ and ‘Torridge’ went to Ministry of Munitions (MoM) Pembrey, Carmathenshire August 1917.
Photos of the BWH&AR stock are here.
Scrapped in 1937.

No.3 – Hudswell Clarke 442 of 1895
0-6-0ST
ex C. Wall (contractor)
Scrapped 1937.

‘Forward’ – Avonside 1655 of 1913.
0-6-0ST
ex T W Ward Ltd. bought 1936
to J Cashmore, Newport April 1957

‘Forth’ – Andrew Barclay 1844 of 1924
0-6-0ST
Hired from T W Ward Ltd. during 1948

‘Sandra’ – Manning Wardle 2046 of 1926
0-6-0ST
Hired from A R Adams, Newport during 1957

Narrow Gauge

Hunslet 1246 of 1916
4-6-0T (WW1 WDLR type)
Sold or scrapped (?)

No.1 (renumbered No.3 in 1954) – Kerr Stuart 3104 of 1918
0-4-0ST
ex-Air Ministry London (arrived Avonmouth by May 1924)
Scrapped November 1954

No.2 – Kerr Stuart 3128 of 1918
0-4-0ST ‘Wren’ class
Bought new
Sold into preservation in Canada in 1954 but has since returned to the UK and now based at Statfold Barn.

No.3 – Hunslet 2384 of 1941
0-4-0ST
Bought new
Scrapped May 1954

The 2ft gauge system on site previously utilised steam but at the time of Gordon Edgar’s visit had a rather decrepit Ruston-Hornsby diesel looking forlorn.

Former ISC Ltd. narrow gauge No.2 loco, a Kerr Stuart ‘Wren’ class 0-4-0ST, has been restored to working order.

Paul Stanford visited the site several times in the 1980s and 1990s. The rail connection re-opened between 1998 and 2003, the last traffic was sulphuric acid to Dalry to Roche Pharmaceuticals. Thanks must go to Paul for these photos and video.

Paul recorded this ride on one of the Sentinel locos in 1998 showing much of the railway (now lifted).

Wikipedia’s entry on the National Smelting Company is copied below:

National Smelting Company
From Wikipedia, the free encyclopedia
The National Smelting Company was a nationalised zinc smelting company in Avonmouth, United Kingdom. It was formed by then Minister of Munitions Winston Churchill to produce mustard gas during World War I.

After World War I, it was bought by private business interests. From 1929 it became part of Australia’s Imperial Smelting Corporation. A.E. Higgs Esq. became the Director of the National Smelting Co. in 1948. The site – also known as the Britannia smelting works – was where the famous Imperial Smelting Process was developed. From 1967, the Avonmouth Works was home to the largest and most efficient zinc blast furnace in the world.

After the cessation of production in the 1990s, it remained open until 2003 as a stock holding and distribution centre. The site is being redeveloped as a 485,000 square feet (45,100 m2) supermarket distribution centre for Asda, and a recycling plant for SITA UK.

BACKGROUND
During the later part of World War I, it was proposed to make Avonmouth Docks the UK centre of production of dichloroethyl sulphide, also known as mustard gas. However, its production was against the Hague Conventions of 1899 and 1907, which explicitly forbade the use of “poison or poisoned weapons” in warfare. Hence covered by the Official Secrets Act, as a cover the Ministry of Munitions under its then Minister Winston Churchill nationalised many small smelting works under the new National Smelting Company (NSC). Before the outbreak of World War I, much of Britain’s zinc had originated in Australia, but had been smelted in Germany. The NSC was hence publicly commissioned to build a new zinc smelting works and sulphuric acid plant at Merebank, Avonmouth Docks.

MUSTARD GAS
Having already built the nearby No.23 filling factory at Chittening, operated by Nobel Explosives, shells there were already being filled with chloropicrin.

Construction of the chemical plant began in 1917, but did not finish until 1923, costing £800,000. The plant came into operation from Spring 1918, producing 20 tonnes (22 tons) of dichloroethyl sulphide using the Despretz–Niemann–Guthrie process per day. The chemical product was than shipped to the main filling factory production site at Banbury, plus secondary sites at Chittening and Hereford. Although the first shells did not arrive in France until September 1918, two months before The Armistice, it was used that same month during the breaking of the Hindenburg Line within the Hundred Days’ Offensive. By November 1918, Chittening had produced 85,424 mustard gas shells.

The human cost of producing mustard gas was high. In December 1918 the chemical plant’s medical officer reported that in the six months it was operational, there were 1,400 illnesses reported by its 1,100 mostly female workers – all medically attributable to their work. Three people died because of accidents, four died from associated illnesses, and there were 160 accidents resulting in over 1,000 burns. At Chittening there were reported 1,213 cases of associated illness, including two deaths which were later attributed to influenza.

OPERATIONAL HISTORY
After World War I, demand for zinc and sulphuric acid greatly fell, and after running into commercial difficulties it was taken over by a group of British industrialists with interests in metals and chemicals, who succeeded in reviving its business under the name Commonwealth Smelting Company. In 1929 the NSC was bought by Australia’s Imperial Smelting Corporation, which in 1949 merged with Zinc Corporation to become Consolidated Zinc.

Throughout the consolidation, the smaller NSC plants were closed down to concentrate production on Avonmouth – now known as the Britannia smelting works – where the famous Imperial Smelting Process was developed. From 1967, the Avonmouth Works was home to the largest and most efficient zinc blast furnace in the world.

Consolidated Zinc, having failed to develop suitable new mining projects, merged from 1962 with the Rio Tinto Company, a mining company. The resulting company, known as The Rio Tinto – Zinc Corporation (RTZ), and its main subsidiary, Conzinc Riotinto of Australia (CRA), would eventually become today’s Rio Tinto Group. With smelting cheaper elsewhere in the world, the site ceased production in the 1990s, but remained open as a stock-holding and distribution centre until 2003.

REDEVELOPMENT
In 2012 SITA UK started redevelopment of the site, but after construction workers were affected by mustard-gas type symptoms, the Ministry of Defence were called in to test and approve the site. However, after MoD approval, a few months later construction workers found a mustard gas shell, which was disposed of by the 11 Explosive Ordnance Disposal Regiment RLC at Porton Down. The site was closed off for a year while experts from the Defence Science and Technology Laboratory conducted a series of tests. In late 2013 MoD clearance was given, allowing the site to be redeveloped as a 485,000 square feet (45,100 m2) supermarket distribution centre for Asda, and a recycling plant for SITA UK.

Timeline of the ISC from Graces Guide

Producers of zinc, cadmium and other metals and certain chemicals

1929 Company formed to acquire National Smelting Co which was subsequently liquidated.

1930 Orrs Zinc White Ltd was acquired by the Imperial Smelting Corporation.

1931 Spelter production at Swansea Vale was stopped because of low prices.

1931 Acquired Wrentnall Barytes Mining Company

1932 Announced completion of preliminary negotiations with ICI, Goodlass, Wall and Lead IndustriesLtd, and the National Lead Co and Titan Company Inc, both of the USA, to develop the titanium industry in the UK. Also had acquired Frickers Metal and Chemical Co Ltd, the country’s largest producer of zinc oxide.

1933 Acquired the Seaton Carew Zinc and Acid works of the Sulphide Corporation, Ltd. and the Delaville Spelter Company.

1933 British Titan Products formed to make titanium dioxide pigments. Jointly owned by ICI, Imperial Smelting Corporation, Goodlass, Wall and Lead Industries and National Lead Co of America. Acquired land from ICI at Billingham to erect a plant.

1934 Fison, Packard and Prentice Ltd entered an arrangement with Imperial Smelting Corporation to establish a joint company National Fertilizers Ltd (set up in 1934) which had a sales subsidiary Fisons’ Fertilizers (Western) Ltd, and also Corby Basic Slag Ltd (set up in 1935) as another subsidiary.

1934 Acquired the Newport Sulphuric Acid Works of the Basic Slag and Phosphate Co.

1937 Zinc smelters, sulphuric acid manufacturers. “Avonmouth” Cadmium. “Crown Special” Zinc.

WWII Increased demand for the company’s products for various munitions and other military purposes; introduced Cuprinol wood preservative. Works at Avonmouth, Seaton Carew and Bloxwich.

1946 Imperial Smelting Corporation and British Metal Corporation made substantial investments in Wolverhampton Metal Co when it became a public company; the two investors intended to play an active part in the management of the business.

1949 Acquired Anglo Austral Mines, Ltd., Fluorspar mines in Durham.

1949 the parent company was Consolidated Zinc Corporation.

1960 Owned 50 percent of Consolidated Beryllium which acquired a beryllium works at Milford Haven

1968 “New Zinc/Lead smelter is world’s largest”. Part of Rio Tinto Zinc Corporation.