Glenbrook Tunnel (1892)

Sir Arthur Streeton's 1891 painting of Fire's On!, depicting a fire in the Glenbrook railway tunnel. (Source: Art Gallery of New South Wales).

The original line of railway was opened in 1867, scaling the escarpment above Emu Plains by the Lapstone Zig Zag. At the top of the Zig Zag the railway followed the route now occupied by the Great Western Highway through Glenbrook as far as Blaxland. When increased rail traffic caused delays on the Lapstone Zig Zag, it was decided in 1891 that a tunnel should be built bypassing the Zig Zag. The tunnel and its new approaches were designed to form an elegant S-shape, starting at the Bottom Points of the Zig Zag and ending at old Glenbrook station (now demolished, on the present Great Western Highway).[3][12]

The building of the tunnel in 1891-2 was contracted to George Proudfoot, whose labourers and their families were established in two substantial camps at either end of the works, one at Glenbrook, the other at Lapstone. Sir Arthur Streeton's famous painting 'Fire's On!', saw the building of the tunnel and the fatal blasting accident which killed Thomas Lawless become a part of Australian mythology as well as railway history.[12] Streeton was spending three months at Glenbrook at the end of 1891 where he was studying and painting the landscape. He had become interested in the construction of the railway tunnel and the engineering feat that was the Zig Zag Railway.[13] The tunnel was also depicted in several other works, both informal and informal. Among these were Cutting the Lapstone Tunnel (1892) and Sketch - Blue Mountains (1891).[3]

The new tunnel opened to traffic on 18 December 1892, but it was never a success, because of the steep incline and the suffocating atmosphere particularly in the west-bound trains. Traffic flow and water dripping from the roof also caused engines to slip badly on the reverse curve. The problem was finally addressed after the Lithgow Zig Zag deviation was completed in 1910 and the railway gangs were moved to Glenbrook. Bypassing Glenbrook Tunnel involved some major works, including a new viaduct[14] over Knapsack Gully to the east and the new line then ran through virgin country south of the old alignment as far as the present Lapstone station and then turned west through a short tunnel under The Bluff and finally north to the present Glenbrook station.[3][12][15]

Initially it was planned to continue using the 1892 Glenbrook Tunnel for up trains. When the new deviation opened on 11 May 1913 the tunnel was still used for east-bound trains. However, the deviation was quickly duplicated and a new "up line was activated in September. Glenbrook Tunnel was last used for trains on 25 September 1913 and old Glenbrook station was closed.[12] The lines in the tunnel were raised and the tunnel left to quietly decay.[3]

In 1913 the Glenbrook tunnel was leased from NSW Railways by Herbert Edward Rowe, an out of work master builder. Previously a Stan Breakspear had fenced off an area close to the tunnel where he kept a bull. The Rowes had the idea of growing mushrooms in the tunnel. They created living quarters from an old circus tent, a small cave and a culvert under the highway. Herbert Rowe built his own mushroom growing beds which were three metres wide with a narrow path down the left side for access and working space. About three quarters of the length of the tunnel was taken up by the beds. When the Rowes renewed their lease in 1936 the Commissioner of Railways warned them that in the event of war, they would be given three months notice to vacate the site. The Rowes are believed to have actually been given only one weeks notice to vacate the site when war broke out in September 1939.[3][16]^: 141–42

In 1930 Australia ratified the 1925 Geneva Protocol which banned the use of asphyxiating, poisonous or other gases in times of war for offensive purposes, following the experiences of chemical warfare during World War I.[3]

A map of Glenbrook Tunnel

Although tear gas was used as early as 1914, it was not until 1915 that poisonous gases were introduced into the battles of World War One. The first was chlorine gas which was introduced by the Germans at the Second battle of Ypres in April 1915. This was followed by the use of phosphene Gas, also introduced by the Germans. These attacked victims' respiratory organs causing coughing and choking.[3]

The Germans used Mustard Gas, a more advanced gas, for the first time at Riga (or Yperite) in September 1917. It caused both internal and external blistering in its victims. The blistering was often delayed and remained in the ground for weeks afterwards making capture of infected trenches dangerous. Protection against mustard gas was far more difficult than previous gases. Casualties decreased during the war with increased preparedness and death from gas became less common. However, often those who were exposed were often unable to seek employment once they were discharged from the army due to the gases effects. Following the Armistice the use of gas was viewed with horror, bringing about the Geneva Protocol. However, it is important to note that while the Protocol prevented signatories using gas for offensive purposes, it did not prevent a nation from manufacturing or importing chemical weapons for retaliatory purposes.[3]

The Geneva Protocol was drawn up and signed at the conference for the supervision of the international trade in arms and ammunition, which was held in Geneva under the auspices of the League of Nations from 4 May to 17 June 1925. France suggested that a protocol be drawn up on non-use of poisonous gases. At Poland's suggestion the prohibition was extended to bacteriological weapons. In the years prior to World War II most major powers ratified the protocol, except the U.S. and Japan. The British reserved the right to waive the protocol if in time of war their enemies disregarded the terms of the agreement. Countries around the world have continued to ratify the Protocol until at least 1991.[3]

Australia's ratification of the protocol was influenced by the experiences of Australian World War One soldiers who had suffered from the deadly and debilitating effects of gas exposure, particularly on the Western Front. Many were killed or maimed as the result of chemical attacks. The physical effects on survivors were clearly visible to those at home upon their return.[3]

Detail of entrance to the Glenbrook Railway and World War Two Mustard Gas Storage Tunnel

By 1937, two years before World War II commenced, Australia was already giving preliminary consideration to the need for procurement of gas for war time defence purposes. Early in 1942 the Japanese southward advance, particularly the fall of Singapore, caused Australia to prepare for possible invasion. Of particular concern was whether Japan would use chemical weapons as it had in China. Australia requested chemical warfare stocks from Britain in March. The response from Britain to supply Australia was swift and the first supplies docked in Australia in May 1942. Later stocks would also come from the United States.[16]^: 1–20 Australia would eventually hold close to 1 million individual chemical munitions weapons, including at least 16 different types of mustard gas. Thirty-five types of chemical weapons were eventually located at fifteen major storage depots across Australia.[3]

The first stocks of chemical weapons destined for the RAAF were stored in the Blue Mountains while those for the army went to Albury. Naval stocks were stored at the Newington Armory in Sydney. The RAAF stocks were stored in disused tunnels, chosen because of the lower fluctuation in temperature, protection from high temperatures and constant humidity. In places such as Malaya, caves were used for the same purposes and the tunnels were anticipated to simulate the same conditions as the caves. Industrial scale production or bulk manufacturing of chemical warfare agents did not and has not taken place within Australia, although some chemical agents have been produced here as by-products of other industrial processes or in bulk for other purposes. There has also been small scale manufacture of chemical agents for experimental and testing purposes.[3][16]^{: 29–30, 128}

The Glenbrook tunnel was one of fifteen bulk chemical storage facilities established in Australia - seven in New South Wales, six in Queensland, one in the Northern Territory and one in Victoria. Six were supervised by the United States, including Kingswood in NSW, and the remainder by Australia. Only four of these included tunnels for storage purposes. These were Marrangaroo, Glenbrook and Clarence in the Blue Mountains and Picton south of Sydney. They were all Australian supervised sites.[16]^: 553 Marrangaroo and Glenbrook were the first of the tunnels established followed by Picton and then Clarence. The Picton tunnel was constructed as part of the original main southern railway line. The remaining three were a part of the Zig Zag railway line. The four tunnels formed the base for the Royal Australian Air Force's No. 1 Central Reserve. The headquarters for No 1CR were based at the combined RAAF-Army depot at Marangaroo, several kilometres from the Marangaroo tunnel. No. 1 CR acted as a central depot for chemical and non chemical stocks and as a replenishment centre for NSW. The location of the tunnels also placed them out of the range of aircraft carriers and out of aerial view, thus protecting them from air attack.[3][16]^: 129–31

The British oversaw the initial establishment of chemical agents handling procedures. On 6 January 1942 the Air Board approved the take-over of the disused 660-metre (2,170 ft) railway tunnel at Glenbrook by the Royal Australian Air Force (RAAF) for the storage of bombs. On 9 August 1942 arrangements for the first intake of chemicals at Glenbrook were advised with material being received from the ship MV Nigerstrromm.[5] When further supplies of chemicals arrived it was decided to move high explosive stocks from Glenbrook and Picton and devote these tunnels to gas stocks alone. Glenbrook housed mainly mustard gas from late August 1942. The RAAF stacked the Glenbrook tunnel from end to end with containers to store thousands of tonnes of mustard gas, a thick fluid that looked like oil. To accommodate facilities for maintenance and inspection, venting and decanting containers and decontamination of damaged hardware, an area was set up in the lower/eastern end cutting leading from the tunnel.[3][16]^: 142–44

Additional shipments of gas in 1943-44 compelled the commissioning of Clarence tunnel to take the overflow. By 7 February 1944 the transfer of chemical weapons stocks from No. 2 Sub Depot, Glenbrook to Clarence Tunnel began. By August 1944 the RAAF decided that chemical weapons stocks and equipment other than obsolete items should be held substantially in forward areas and that No. 1 CR would become a transit point rather than a storage area to facilitate the supply of chemical weapons to forward unit should retaliatory chemical warfare action be sanctioned. two storage locations were subsequently chosen in north eastern Australia.[3][16]^{: 129–131, 142}

During the peak period for the arrival of chemicals from Great Britain and the African desert zone Glenbrook railway siding was inadequate for the transport operations and associated influx of railway wagons and motor vehicles. Therefore, trains were kept at Penrith and batches of 14-20 wagons brought to Glenbrook as required.[3][16]^: 142–44

In 1946, following the end of the war, the Australian Defence Committee agreed to the Army and RAAF requests to dispose of chemical ammunition. The Australian Government faced a dilemma as to how to dispose of the stocks of chemicals. Neither the Army or the Air Force had experience with disposal. As a result, trials were conducted to determine the best form of large scale chemical destruction. Burning, sea dumping and venting were found appropriate for the different types of chemicals. Fire was found to be the most appropriate for mustard gas. Gas was burned from storage sites at Talmoi and 88 Mile. The stocks at Marangaroo and Glenbrook were the last to be burned. The disposal took place in the Newnes State Forest during February and March 1946 when 2,000 tonnes (2,200 short tons) were incinerated. Post war inspections showed that the burn had been incomplete and redisposal operations were conducted between 1947 and 1949, including reburning some items and the use of bleach. Final decontamination took place in 1980 when approximately 2,500 tonnes (2,800 short tons) of mainly soil residue were removed from the Newnes State Forest burn site to the nearby Marrangaroo Ammunition Depot to be burned in a pit and bleached.[16]^: 308–10 Glenbrook later reverted to its former use as a mushroom farm.[3]

Glenbrook was considered the most pleasant of the tunnel depots by the men who worked with the gas. The site was described in 1943 as about 5 kilometres (3.1 mi) into the bush. The camp consisted of the headquarters, orderly room a store, alcove for maintenance carpenter, mess hut with a big stone fireplace and an open fire to cook on, masonite and wooden framed sleeping huts which had replaced tents. The huts had shutters at the top and bottom which could be propped open shower and toilet blocks and a small transport section hut. Workers were required to do maintenance on the containers wearing gumboots, rubber gloves and heavy woollen clothing. Small burns were common if the men got gas on their skin. During the summer months RAAF staff from the Glenbrook camp were called out to fight bushfires.[16]^{: 142–152} The purpose of their presence at Glenbrook was a long-held secret as was the testing and later disposal of the gas.[3]

During operation the s curved, 650-metre (2,130 ft) tunnel was long and dark with widely spaced lighting. On the left hand side at the start of the tunnel were small containers, canisters in wooden crates. About midway canisters were located on one side and drums on the other. Further along, the sides that the canisters and drums were stored on were reversed. The tunnel had very little clearance, making it difficult for the trucks to back into the tunnel to load and unload the chemicals.[16]^: 150–53 The exterior ends of the tunnel were constructed of brick with stone capping. During WWII the RAAF installed a concrete grid floor in the tunnel and installed a telephone system for security purposes. It was apparently initially used by the RAAF to store 227-kilogram (500 lb) bombs.[3]

Post World War II, all four tunnels were used for mushroom growing purposes. Glenbrook tunnel has since been abandoned. In 1992 the lessee commenced growing exotic mushrooms not previously produced in Australia. Other tunnels not used for mustard gas storage have also been used as mushroom tunnels, including one at Mittagong and another near Helensburgh. The Marrangaroo storage tunnel has also been abandoned, while the Clarence tunnel forms part of the Zig Zag Tourist Railway and Picton has become a tourist attraction with a "ghostly past". The World War II history of the tunnel's use was not widely known until the early twentyfirst century. This "hidden history" was the subject of significant interest when it was finally made known.[3]

In 2021, it was announced that the state government will be funding works to transform the tunnel as a publicly accessible walking track, cycleway, and heritage tourist attraction, as well as better connecting the Lower Blue Mountains to neighboring Leonay and Penrith. [17]

Part of the interior of the tunnel in 2010

As at 15 December 2010, the tunnel structure appears to be in very good condition visually. Mushroom racks and associated infrastructure and infil at the end of the tunnel appear to be non structural and easily reversed if desired.[3]

The tunnel structure does not appear to have been significantly altered. The most obvious alterations are the apparent replacement of the railway tracks and ballast with a concrete floor, and removal of any purpose built facilities associated with the mustard gas storage.[3]

• 1913 - Railway lines removed
• c. 1913 - mushroom growing beds installed
• c. 1939-42 - mushroom growing beds removed for establishment of mustard gas storage
• Post 1945 - converted for mushroom growing[3]

• "Bunkers, Tunnels and Fortifications in Australia during World War Two". 2009.
• Gillis, Richard G. (1985). The Gillis Report: Australian Field Trials with Mustard gas 1942-45 (PDF). Peace Research Centre, Australian National University.
• International Committee of the Red Cross (2005). "International Humanitarian Law - Treaties and Documents".
• National Gallery of Australia (2010). "Turner to monet. The Triumph of Landscape Education Resource".
• Plunkett, Geoff (2009). "Chemical Warfare in Australia".
• Plunkett, Geoff (2007). Chemical warfare in Australia. Australian Military History Publications. ISBN 978-1-876439-88-0.
• Pratten, Christopher; Irving, Robert (1993). Lapstone Hill Tunnel Conservation and Management Plan.
• Wildman, Don (2009). "Cities of the Underworld - Alcatraz Down Under". YouTube.

This Wikipedia article contains material from Glenbrook Railway and World War Two Mustard Gas Storage Tunnel, entry number 01861 in the New South Wales State Heritage Register published by the State of New South Wales (Department of Planning and Environment) 2018 under CC-BY 4.0 licence, accessed on 2 June 2018.