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Report - - Box Tunnel East Portal (Sidings to Tunnel Quarry and CAD), Wiltshire - February 2015 | Underground Sites | 28DaysLater.co.uk

Report - Box Tunnel East Portal (Sidings to Tunnel Quarry and CAD), Wiltshire - February 2015



Bertie Bollockbrains

The Spice Must Stop
Regular User
#1
Box Tunnel is a railway tunnel between Bath and Chippenham, dug through Box Hill and is one of the most significant structures on the Great Western Main Line. The tunnel is 1.83 miles in length, straight, and descends a 1 in 100 gradient from the east. It was originally built for the Great Western Railway under the direction of the GWR's engineer Isambard Kingdom Brunel.

This report is simply about a small secondary portal that exists at the Eastern Portal, and is not me entering the main Box Tunnel - being a live high speed rail line that would have been very silly and fatal. This secondary portal dates from at least 1886 and served Tunnel Quarry and later the WW2 era Central Ammunition Depot.

History

Construction of Box Tunnel began in December 1838, divided into six isolated sections. Access to each was via a 25 foot diameter ventilation shaft, which ranged in depth from 70 feet on the eastern end to 300 feet towards the western end. All men, construction equipment, materials and 247000 cubic yards of extract had to go in and come out via steam powered winches. The only lighting was via candlelight, which were consumed at the rate of one tonne per week, which was equaled by the weekly consumption of explosives. At the height of activity about 4000 men were employed, and perhaps a hundred lost their lives. Effective completion of the tunnel was in April 1841. When the two ends of the tunnel were joined underground, there was found to be less than 2 inches of error in their alignment.

The famous Corsham quarries, which produced Bath limestone, were in the hillside above the tunnel. By 1886 the East Portal of Box Tunnel was subsequently altered by the construction of a separate portal into Randell & Sanders' Tunnel Quarry (which lay north of the tunnel) through its own tunnel mouth a few yards forward of Brunel's portal. The siding extended over half a mile into the hillside to a loading platform.

Victorian Era Photo of the East Portal
Box-Bath-Stone-Mine-Archive-Album-001_zps8b452a77.jpg


In 1936 Tunnel Quarry was acquired by the War Office as one of the four sub-depots of the Corsham Central Ammunition Depot, a vast underground munitions storage facility in the Corsham quarries. The Royal Engineers undertook the conversion works, which probably included the brick alterations to the East Portal. Most of the ammunition during the war arrived and left by the former quarry siding, whose portal appears to have been remodeled in reinforced concrete.

WW2 era photo of the East Portal
sc_cad1_war_157_zps84d19e47.jpg


Map of CAD - Tunnel Quarry Section. Red arrow shows the Box Tunnel East Portal
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CAD closed at the end of WW2 hostilities, although was kept in an operational condition until the 1950s. The sidings were then cleared and not used again until the mid-1980s when a museum opened for a short period on the site. Today the former mine/CAD is used for secure commercial document storage.

Trip Report

This trip gave me my first ever Urban Explore trouser-ripping experience. Thank God the car wasn't too far away. I guess there will be more of those to come. Anyways onto the photos:

First view of the siding looking in
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Leads to bricked doorway after about 50 metres. Only dynamite will allow access to Tunnel Quarry beyond and guess what I had forgot to pack.
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And looking out
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A WW2 era office lies to the side of the tunnel
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Old light switch
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Light fittings
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Electrical thingys
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This is a stalagmite rising from the floor
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Thanks for looking, now I need to go and online shop for some Kevlar strength trousers. I'm sitting here on the sofa with no trousers on and it's alarming the wife a bit. :D
 
Last edited:

huey

28DL Full Member
28DL Full Member
#2
Re: Box Tunnel East Portal (Sidings to Tunnel Quarry and CAD), Wiltshire - February 2

Now I've met you ive no doubt why the wife's nervous...very nice report,very interesting history too. Nice one :thumb
 

Oort

Fear is the little death.
Regular User
#3
Re: Box Tunnel East Portal (Sidings to Tunnel Quarry and CAD), Wiltshire - February 2

Fair play mate well done! Never thought I'd see inside :thumb
 

Lenston

Bajo Tierra
Regular User
#4
Re: Box Tunnel East Portal (Sidings to Tunnel Quarry and CAD), Wiltshire - February 2

Quite nice to see that and well worth a look :)
 

wellingtonian

Subterráneo
Regular User
#5
Re: Box Tunnel East Portal (Sidings to Tunnel Quarry and CAD), Wiltshire - February 2

So that's where you ended up then :thumb
Well worth a look I guess.
 

pigdog

28DL Full Member
28DL Full Member
#6
Re: Box Tunnel East Portal (Sidings to Tunnel Quarry and CAD), Wiltshire - February 2

cool
 

Dark Prince

28DL Regular User
Regular User
#7
Re: Box Tunnel East Portal (Sidings to Tunnel Quarry and CAD), Wiltshire - February 2

So thats what the other side of the wall looks like!. I was lucky enough to visit the 'hot' side a few years ok.

DP
 

The Wombat

Mr Wombat
28DL Full Member
#8
Re: Box Tunnel East Portal (Sidings to Tunnel Quarry and CAD), Wiltshire - February 2

interesting stuff :thumb
 

Oxygen Thief

Admin
Staff member
Admin
#9
Re: Box Tunnel East Portal (Sidings to Tunnel Quarry and CAD), Wiltshire - February 2

Your history isn't quite correct there mate, you've copied some of Monkton Farleighs history.
 

Bertie Bollockbrains

The Spice Must Stop
Regular User
#10
Re: Box Tunnel East Portal (Sidings to Tunnel Quarry and CAD), Wiltshire - February 2

Ahh Thanks OT. I see where I got the history wrong - Tunnel Quarry was never part of the underground museum during the 1980s as implied above and in fact remained live for MOD use for much longer than what I implied. It is of course the Monkton Farleigh side that was the 1980s museum and then secure document storage.
From an online source for Tunnel Quarry "The quarry is still strictly controlled by the MOD as several areas are still classified including the Command and Control Computer Centre (CCC) in the eastern part of the quarry, which is accessible via lift from a discreet bunker style entrance in Peel Circus. Another area known as South-West Control is also still in use at the opposite end of the quarry, this area was originally set a side as storage district 1 but it was never converted, it was later converted it to a telephone exchange and switching room, it's current day use is unknown."

Just shows how much I need to educate myself on what exactly is underground in this area. As you know I have been assisting in arranging Nick McCamley author of Second World War Secret Bunkers and other books to deliver a talk at Yatton Keynell. This talk will most probably be sometime in March. I will be giving the date and details to those members who have already expressed an interest in attending when known.
 

Budice

28DL Full Member
28DL Full Member
#11
Re: Box Tunnel East Portal (Sidings to Tunnel Quarry and CAD), Wiltshire - February 2

Could you pass the dates onto me as well please Bertie?
 

drhowser

Bespectacled & irrelevant
Regular User
#12
Re: Box Tunnel East Portal (Sidings to Tunnel Quarry and CAD), Wiltshire - February 2

I was so excited when I saw Box tunnel! I thought you'd done the trains bit..
 

Bertie Bollockbrains

The Spice Must Stop
Regular User
#13
Re: Box Tunnel East Portal (Sidings to Tunnel Quarry and CAD), Wiltshire - February 2

Could you pass the dates onto me as well please Bertie?
Noted... will send PM when I know myself

"I was so excited when I saw Box tunnel! I thought you'd done the trains bit.."

What!!! Are people around me wanting to get run down by the 9.52 London to Bristol :( But but me is nice really... ask err err my mother
 

Ordnance

Moderator
Moderator
#14
Re: Box Tunnel East Portal (Sidings to Tunnel Quarry and CAD), Wiltshire - February 2

All of the Ammunition Storage Districts of CAD Corsham were still in use till 1964 when the ammunition depot closed and stocks were transferred to CAD Longtown & Kineton and till around 1966 when the Royal Engineers abandoned their underground workshop, after which the site reverted to care and maintenance under the Ministry of Public Buildings and Works till the late 70's