Corsham Tunnels

Part of a Government underground site near Corsham in Wiltshire, which was a potential relocation site for Government in War has now been declassified. The site remains part of the MoD estate.

To view all Corsham Tunnel images, please go to
http://www.defenceimagedatabase.mod.uk/fotoweb/
and type 'Corsham' into the Search.

Photographs of the former potential relocation site
for Government in War

Coffee Machine	Kitchen	Message Distribution Room	Message Distribution Room
Paper	Switchboard Room	Switchboard	Tunnels

History of the Tunnels

The Bath stone (Oolite Limestone) has been quarried within 20 miles of Bath since Roman times, with evidence of Roman Villas at Box and Colerne not to mention the Baths in the City itself. It was really the Romans that developed the quarrying of stone in the area, due to their imported knowledge and craft in the trade. It was however all done in open cast quarries. The “Golden” age of our quarries was from 1850 - 1910 when, with the advent of Great Western Railways and building of Box Tunnel, an easy access to the deep stone beds was discovered and a good transportation system for the cut stone was put into place.

Central Ammunition Depot (CAD)

Midway between the 2 great wars the War office decided that measures were necessary to guard against attack on our ammunition stocks by hostile aircraft. So the country was searched for suitable sites. In 1935 war was imminent and the go ahead was given to build 3 ammunition sub-depots at Monkton Farleigh, Eastlays Ridge and here at Tunnel Quarry - collectively known as CAD.

The Bombs Roll In

It was estimated that it would take 4 years to complete, but in fact it was opened in April 1938. Britain’s rearmament plan was the number 1 priority and the first “District” was ready to take ammunition in May 1938, but a means of bringing the ammunition in had to be found. One of the vertical airshafts was converted and a steam winch installed, the baskets of ammunition were lowered down it. This continued as a temporary measure until the rest of the construction caught up.

Tunnel Sub-Depot when finished consisted of 10 districts each with approx. 3 acres of floor space (5 acres gross). Air was drawn in by large fans via "vertical pressure shafts" off from a huge fan called the "Clift Drift Inlet" (CDI) Fan via the old workings to the west. The air was heated and distributed via trunking, other fans drew the air out and this produced a "stable" atmosphere of 65°F and 80% humidity.

Transportation

Ammunition arrived at the sites by either road or rail, all the quarries had a surface loading platform (SLP) Where lorries could load or unload. Tunnel Quarry had a full gauge railway underground completed with 2 platforms, the other quarries had conveyor belts which led to their own railway sidings. Movement underground was originally "Endless Rope and Haulage Truck System" similar to that employed in coalmines. But the noise of these trucks moving over miles of track and points was horrendous; not to mention the danger when trucks of ammunition were derailed or became detached from the cable. So in 1940 it was decided to install conveyor belts in all but Ridge Quarry which handled RAF bombs which were too heavy for the belts. Approximately 7.5 miles of heavy-duty conveyor belting was installed at the other two sites. Whilst performance figures were deemed unnecessary the daily load for the 3 sub depots was between 700 and 3000 tons. The largest daily figure for tunnel Sub-Depot was 1542 tons (28th March 1942).

Underground Accommodation

In 1941 a Barrack Block was constructed at Tunnel Quarry (between 1 and 2 districts), it could accommodate 300 personnel and was said by the ROAC Gazette to be "Magnificent" with Bars and Messing areas. Tunnel Quarry also had a “Power Station” with 2 huge diesel generators capable of supplying power for a small town; it also had its own underground lake for drinking water etc. Sewerage and Flood pumps were also provided. Essentially there was no need to go above ground and during the war many personnel stayed underground to help keep the installation a secret.

Arrival of the RAF

On 6th February 1942 it was decided to establish a new Communications Centre to serve the South West of England, by July 1943 the work costing £50,000 was completed and by August 1943 the Centre was fully operational with 420 personnel.

This Centre occupies No 1 District, which was never commissioned for ammunition storage. In the early 1960’s the Royal Ordnance Corp moved out and took the last remaining ammunition with them. To this day many of the districts lie empty.

One of the 'Horse Race Meeting' murals found in the old dining area of the operative’s canteen of the aircraft engine factory. The Indian Rope Trick depicts the side shows that formed part of Race meetings before the 2^nd World War. All of the murals were painted in 1942 by an artist called Olga Lehmann who was working in the British Film industry; she was approached by the architect who had helped design the factory and commissioned to paint the murals.

Gypsy encampment, a certainty at any Race meeting.

This photo shows a now disused Quarry in the normal abandoned state. The narrow gauge railway tracks were used for the haulage of the block of stone. Normally the trucks were pulled by pit ponies to a slope shaft entrance; from there they would be winched to the surface by steam winch. Bath Stone Quarries are self supporting structures, very few pit props were used and the foreman ganger would decide on the amount of stone taken out and the span of the roof. Most of the support pillars taper from the roof and for a very good reason, the quarrymen were paid by the amount of stone they quarried and the closer to the floor they worked it was easier to remove bigger blocks. This practice was known as ‘robbing the pickers’.

The scene in one of the storage districts showing the method of stacking shells. Note the supervisor in the background not one to miss out on a photo opportunity.

This photo shows the conveyer belt in the main gallery of Tunnel Quarry.The gravity fed extension roller conveyers joined the district conveyer belts to the main gallery belt. Positioning the shells correctly on the belt was imperative to ensure the smooth operation of the system.

Back to the old Quarry days, ‘the end of a long hard day’. Note the number and size of the ‘pit ponies’ used for hauling the blocks.

One of the Quarry cranes in use, the average weight of a block of bath stone is between three and five tons. The chap in the suit and tie is obviously the foreman ganger taking advantage of the photo shoot.

Once the block of stone had been moved from the workface it would be ‘squared off’ using hand axes or the saws. The big bladed saw on the left of the photo is called a ‘frig bob’.

This chap is a ‘Picker’ and his job was to pick out the top of the workface going back into the rock to a depth of about 8 foot. This chap appears to have found a fairly easy face as he is nearly standing erect. He is working at the level of the roof and uses a selection of picks that increase in length the further back the channel is required.

The CAD tunnel entrance photographed in 1943. The eastern portal of Brunels Tunnel is just out of shot to the left. The MOD had built over the old quarry entrance and extended it outwards away from the railway tunnel entrance, this was to make a reception area for the ammo trains. Note the loco pushing the carriages out of the CAD; it is one of the small diesel loco specially built for work in the CAD. Also note the ‘Bobby’ is the first line of defence.

An old postcard depicting the eastern portal of Brunel’s and the quarry entrance at about 1910 – 1914. Two things of note about this picture. Firstly the eastern portal was designed by Brunel to be an optical illusion, as approached the entrance looks a lot larger than it actually is. Secondly it is claimed that the façade of the original quarry entrance was actually designed by Brunel to mirror the design of his own tunnel.

The Royal Engineers workshop as it is today, abandoned in 1966 and left to gently decay. The yellow and black markings on the trucks show that they were used to move the ammunition around the districts in the northern service tunnel or Hudswell drift. These trucks were not used by the REs on the narrow gauge rail system (note the wide flanges on the wheels, these were used in the concrete tracks found only in the Northern Service tunnel).

For further information. please go to UK Defence Today

Requests for visits to Military Establishments must be cleared through the appropriate MoD channels. Requests should be sent, in writing, to: Wing Commander Steve Röver-Parkes, Commanding Officer Joint Support Unit Corsham, Rudloe Site, Park Lane, Corsham, Wiltshire SN13 9NR.

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Last Updated: 24 Nov 05