Tunnels/ventilation shafts

[ess]

What determines how many ventilation shafts are required for a tunnel. Take the Bramhope tunnel for example.. it has two I think plus a tower off in some fields. Why two - why not three or one? (or none)

 

[t o m]

Sometimes the digging of ventilation shafts would speed up the digging of the tunnel. Say you had a tunnel with a ventilation shaft in the middle, you could have two teams digging in from the outsides of the tunnel and two teams digging outwards either way from the centre.

 

[Ploughman]

In the case of Bramhope.
Ther may be 2 vent shafts now but during construction there were about 4 - 5 more.
The remaining shafts were kept open to provide ventilation for clearing smoke and steam from Steam locos.
Same situation arises in nearly every tunnel actual shafts originally constructed does not match what is in place now.
Some of these blind shafts are just capped over others are backfilled.

 

[Gathursty]

Upholland tunnel has 3 ventilation shafts IIRC. I can't be certain if there were any more built for it's construction but they are easy to make out on the hilly farmland behind the school.

 

[RichmondCommu]

Blea Moor tunnel had seven ventilation shafts sunk to aid its construction. Out of those three still exist and make the walk over Blea Moor to Dentdale an easy one. The spoil from when the shafts were sunk can also be seen.

 

[edwin_m]

Sometimes when construction shafts are infilled or capped the locations are later lost. Probably the most horrible consequence of this was the Swinton tunnel collapse.

http://www.railwaysarchive.co.uk/doclisting.php?&event=475&submit=go

 

[yorksrob]

Sometimes when construction shafts are infilled or capped the locations are later lost. Probably the most horrible consequence of this was the Swinton tunnel collapse.

http://www.railwaysarchive.co.uk/doclisting.php?&event=475&submit=go

As a result of this, I believe it is now the practice to mark the location of filled in construction shafts in tunnels.

 

[slipperysyd]

The Severn rail tunnel is actually fed with positive pressure air at Sudbrook shaft to clear the tunnel as any shafts mid tunnel would be in the estuary!

Syd.

 

[plastictaffy]

Speaking of shafts in tunnels - anyone know Kilsby tunnel on the WCML?? It seems to have been built in at least 3 seperate chunks. The air shafts are actually wider than the tunnel itself. Why would it have been built that way??

 

[Llama]

Morley Tunnel is the same. Lineside phones are in the recesses formed by the air shafts on the Down side.

 

[Flamingo]

The Severn rail tunnel is actually fed with positive pressure air at Sudbrook shaft to clear the tunnel as any shafts mid tunnel would be in the estuary!

Syd.

They did try one, it didn't work!

(I'm being factious, I know that they accidentaly dug through into the Severn during construction, for the pedants out there).

 

[kevconnor]

There has also previously been a derailment caused by the significant accumulation of ice in a ventilation shaft at Summit Tunnel in Todmorden becoming dislodged and falling onto the track.

http://www.raib.gov.uk/publications/investigation_reports/reports_2011/report162011.cfm

 

[Texas]

They did try one, it didn't work!

(I'm being factious, I know that they accidentaly dug through into the Severn during construction, for the pedants out there).

I think that when the tunnel was flooded during construction it was in fact because they struck into a fresh water aquifer (later known as the Great Spring) and this halted construction until pressure tunnel workings were pioneered.

Until recently I think that the water that still floods continuously into the tunnel ( millions of gallons per hour!) was pumped out and used by the local brewery (Interbrew) to produce Stella no less.

Paul.

 

[Flamingo]

It flooded twice, once from the great spring, once from the Severn. http://en.m.wikipedia.org/wiki/Severn_Tunnel#/search

 

[181]

If Wikipedia is to be believed, Sapperton Tunnel has had problems with disused shafts beneath the track, as they were dug to the depth at which the tunnel was originally planned to run.

 

[3141]

Speaking of shafts in tunnels - anyone know Kilsby tunnel on the WCML?? It seems to have been built in at least 3 seperate chunks. The air shafts are actually wider than the tunnel itself. Why would it have been built that way??

I don't know for sure, but I've always assumed that as it's a long tunnel, and very early in terms of railway development, they may have felt they needed wide shafts for ventilation purposes. Or maybe they weren't 100% confident about their construction techniques and thought that having the shaft walls outside the tunnel walls would make things a bit safer.
--- old post above --- --- new post below ---
After I'd posted what I'd written yesterday I remembered that in addition to the large shafts in Kilsby Tunnel there are several smaller ones. That tends to invalidate the second sentence of my previous post.

I've looked on Google Earth, where it appears that the smaller shafts may have been capped, though I'm not 100% sure.

Maybe the large shafts were the ventilation shafts, and the smaller ones a series of access points for tunnelers along the route, dividing the work on a long tunnel into shorter sections.

I first travelled through Kilsby in 1958, and remember being surprised then at the size of the larger shafts. My recollection, which may be wrong, is that at that time you could see light coming down the smaller ones as well. I haven't been through it recently.

 

[Bald Rick]

I don't know for sure, but I've always assumed that as it's a long tunnel, and very early in terms of railway development, they may have felt they needed wide shafts for ventilation purposes. Or maybe they weren't 100% confident about their construction techniques and thought that having the shaft walls outside the tunnel walls would make things a bit safer.
--- old post above --- --- new post below ---
After I'd posted what I'd written yesterday I remembered that in addition to the large shafts in Kilsby Tunnel there are several smaller ones. That tends to invalidate the second sentence of my previous post.

I've looked on Google Earth, where it appears that the smaller shafts may have been capped, though I'm not 100% sure.

Maybe the large shafts were the ventilation shafts, and the smaller ones a series of access points for tunnelers along the route, dividing the work on a long tunnel into shorter sections.

I first travelled through Kilsby in 1958, and remember being surprised then at the size of the larger shafts. My recollection, which may be wrong, is that at that time you could see light coming down the smaller ones as well. I haven't been through it recently.

My understanding - and I have no source for this other than 'someone told me once' (but that someone was an engineer on the line in question) - is:

In the early days, rails were routinely turned to even out wear on the gauge face, ie the bit the wheel flanges can touch. This was before the mechanics of wheel conicity etc were understood, when rail wear was much greater than it was a few decades later. So as well as being used as construction access, the big shafts (diameter just over 60ft?) were used to shorten the distance that rails had to be moved to to enable turning.

 

[Trog]

My understanding - and I have no source for this other than 'someone told me once' (but that someone was an engineer on the line in question) - is:

In the early days, rails were routinely turned to even out wear on the gauge face, ie the bit the wheel flanges can touch. This was before the mechanics of wheel conicity etc were understood, when rail wear was much greater than it was a few decades later. So as well as being used as construction access, the big shafts (diameter just over 60ft?) were used to shorten the distance that rails had to be moved to to enable turning.

Two things the shafts were built in 1838, and rails did not get to 60'-0" long until ~1890. Also you would not be very popular with your gang if you made them carry a rail several hundred yards to a shaft, dismantle the signal that stood there, turn the rail, re-erect the signal and carry the rail back again. When you could get the same effect by carrying the rail 4'-8 1/2" and transposing it. I think the reason for the large shafts is to give room to work past the pumps needed to keep the tunnel dry during construction. As the pump would need to be at track level as a surface mounted pump would be limited to sucking water up by about 32'.

 

[krus_aragon]

Here's another possible explanation (which I can't claim as my own):

[The] great ventilation shafts (and 10 smaller ones, which aren’t as pretty, and not listed) helped reassure nervous Victorian train travellers that they wouldn’t be choked to death by smoke contained with the tunnel, by allowing the smoke to escape upwards and outwards. The Victorians were both fascinated and terrified by train travel, which really was a brand new technology to them, and one they didn’t really understand.

This tunnel was the longest ever, at the time.

 

[Bald Rick]

Two things the shafts were built in 1838, and rails did not get to 60'-0" long until ~1890. Also you would not be very popular with your gang if you made them carry a rail several hundred yards to a shaft, dismantle the signal that stood there, turn the rail, re-erect the signal and carry the rail back again. When you could get the same effect by carrying the rail 4'-8 1/2" and transposing it. I think the reason for the large shafts is to give room to work past the pumps needed to keep the tunnel dry during construction. As the pump would need to be at track level as a surface mounted pump would be limited to sucking water up by about 32'.

Good points well made!

 

[Cliveblackpool]

Here's my 3 penny's worth!
If they were using explosives, as they progressed maybe a shaft to cause a through draft to vent the choking poisoness fumes? You can light a fire underneath the shaft to force a draft.

 

[Trog]

Here's my 3 penny's worth!
If they were using explosives, as they progressed maybe a shaft to cause a through draft to vent the choking poisoness fumes? You can light a fire underneath the shaft to force a draft.

That would only work once the tunnel had been completed and there was a connection through it to a down cast shaft where air could be fed into the tunnel. Also if you did do that it would work better with a smaller shaft rather than a large one, as it would draw better. Which is one of the reasons chimneys got smaller over time.

 

[infobleep]

Here's another possible explanation (which I can't claim as my own):


This tunnel was the longest ever, at the time.

When the tunnel was first opened, we're their still open carriages running, aka 5th class? If so how bad would the fumes in a tunnel be?

I've sometimes wondered what it would be like to travel in an open carriage through tunnel or working a steam engine with its open sides to the cab, or go back far enough no roof, through a tunnel.

Sent from my Nexus 5 using Tapatalk

 

[edwin_m]

Perhaps less of a problem than you might think in places like Kilsby, because the train service would have been relatively infrequent so the fumes would have time to dissipate between trains. It certainly became a big problem on the Metropolitan though, when trains where much more frequent.

There have been a few cases of traincrews rendered unconscious by fumes in tunnels, for example at Combe Down tunnel where the train then ran away and was wrecked in Bath Green Park goods yard. This was a particularly long and narrow single track bore on a steep gradient with no ventilation shafts.

http://www.railwaysarchive.co.uk/docsummary.php?docID=1999

 

[infobleep]

Then perhaps we should bring back open carriages. Imagine travelling at 110 miles an hour in an open carriage. Lol.

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[theageofthetra]

Re open carriages and steam in long tunnels. I have been on the open front platform of a brake van whilst going uphill in the spiral tunnel on the
Bohinj railway in Slovenia. The loco was running tender first so I was about 6 ft from the Skoda built Kriegslok type loco. A fantastic experience but the noise and fumes and to be experienced to be believed. I eventually realised it would be wise to retire to the confines of the van when a red hot cinder set light to my hair!
--- old post above --- --- new post below ---
I was on a Railtour back from the Wolstyn May day parade to Berlin a few years ago and it got up into the high 80's behind a pair of Romanian built diesels. The last 3 coaches consisted of open veranda 1920's 3 wheelers and it was a bit bracing (& very bouncy!) Out on the back verandah

 

[infobleep]

Thanks for the interesting stories. Would health and safety allow such services now? I don't fancy a cinder setting light to my hair though!

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[theageofthetra]

Would like to point out both happened in the last 5 years on a European main line!

 

[Philip]

Standedge tunnel doesn't have any shafts because the railway tunnel is connected to the canal tunnel (which does have shafts) with frequent side adits, so the ventilation come from the canal tunnel through these into the railway tunnel.

At Harecastle in Kidsgrove/Tunstall the live canal tunnel doesn't have shafts - instead ventilation is in the form of a fan at the portal which sucks air in from the far end of the tunnel. There are shafts on Harecastle hill which either belong to the old railway tunnel or the older disused canal tunnel.

Netherton tunnel near Dudley is a canal tunnel built in the railway age and built very much in the style of a railway tunnel. This has plenty of ventilation shafts, I'm guessing later tunnels had more construction shafts kept open for ventilation.

 

[table38]

Standedge tunnel doesn't have any shafts because the railway tunnel is connected to the canal tunnel (which does have shafts) with frequent side adits, so the ventilation come from the canal tunnel through these into the railway tunnel.

Thanks, I never realised that! Lots more fascinating information on the ventilation arrangements at Standedge here: http://www.forgottenrelics.co.uk/tunnels/standedge.html