Harecastle Tunnel - inexperience

[Barry]

One thing not mentioned so far (I think) is that tunnels are cold (maybe about 10C all year round) and in places often have water streaming from the roof. So wear a warm waterproof coat and hat, nothing worse than being cold and miserable in a long tunnel.

 

Yes and a broad brimmed hat at that - if you have one

[cuthound]

I have to say that is not my memory, and I thought it was constructed in situ, rather than pre-assembled.

 

Either way, the "tubes" are certainly far from cylindrical.

Just googled for Galton Tunnels and found this, which seems to correlate with my memory that it was prefabricated.

 

https://books.google.co.uk/books?id=CQ08PgugTOsC&pg=PA32&lpg=PA32&dq=galton+canal+tunnel&source=bl&ots=gEFgeghkvb&sig=nOLJHXy56cJ8vOpLQGy950zQ3aI&hl=en&sa=X&ved=0ahUKEwjpn-6oksrLAhUBKA8KHbBaCxM4ChDoAQgmMAU#v=onepage&q=galton%20canal%20tunnel&f=false

 

It also gives the construction date as 1974, which is earlier than I thought.

[Cheshire cat]

Every time I have gone through Harecastle they seem to have changed their safety procedures. Last time was in October. If your horn isn't of the right standard they do lend you an airhorn for the trip.

 

Ours needs fettling. It's feeble. Another job for the easter holiday.

[cuthound]

Every time I have gone through Harecastle they seem to have changed their safety procedures. Last time was in October. If your horn isn't of the right standard they do lend you an airhorn for the trip.

 

Ours needs fettling. It's feeble. Another job for the easter holiday.

I gave up trying to fettle mine to make it louder, and couldn't find one to fit (it is at the end of a brass trumpet on the headlight stand).

 

I bought one of these:

 

https://marinestore.co.uk/Merchant2/merchant.mvc?Screen=PROD&Product_Code=NT3119&Category_Code=rechargeable_fog_horns&Store_Code=mrst&gclid=CM6ip7yVyssCFawp0wodbQEEHw

 

Very loud, as I found out when I tested it under the hatches with the back doors closed .

[alan_fincher]

Just googled for Galton Tunnels and found this, which seems to correlate with my memory that it was prefabricated.

 

https://books.google.co.uk/books?id=CQ08PgugTOsC&pg=PA32&lpg=PA32&dq=galton+canal+tunnel&source=bl&ots=gEFgeghkvb&sig=nOLJHXy56cJ8vOpLQGy950zQ3aI&hl=en&sa=X&ved=0ahUKEwjpn-6oksrLAhUBKA8KHbBaCxM4ChDoAQgmMAU#v=onepage&q=galton%20canal%20tunnel&f=false

 

It also gives the construction date as 1974, which is earlier than I thought.

 

I guess it depends on what you mean by "pre fabricated"?

 

I think many describe the new section of Blisworth as being built from pre-fabricated parts, but it of course does not mean that 3/4 mile of tunnel was delivered as an already completed part.

 

Surely the tunnels near Galton are simply too large that they could have been brought there as already cast "tubes"?

 

I still think that, like a pre-fabricated house, they wee put together on site from pre-fabricated parts.

 

There must be pictures of the construction, but I'm damned if I can now find one!

 

EDIT:

 

Yes, I am correct, the new book "The Birmingham Canal Navigations 1950 to 1977 as seen through the lens of Philip Weaver" shows two pictures of the construction of Galton Tunnel. It shows a massive scaffolding type sructure over which pre-fabricated sections are being erected.

 

It also looks like the actual canal bed and side walls are in fact a simple oblong section channel, probably cast in situ, and not part of the arch over the top.

 

As the pictures are copyright, I had better not reproduce them here.

Edited March 18, 2016 by alan_fincher

[BruceinSanity]

I love including pictures in posts, you have probably noticed. It's a tricky line to tread though. I'm happy to just use pictures from Wikipedia or from businesses websites, it could be seen as advertising

 

Ones from individuals are a bit more problematic. I don't want to steal their property. One option is to add a link, like I did. Another is to make the image into a link to the originating page, but that isn't as clear

 

I do worry about stuff- perhaps I should get out more

 

Richard

I think "fair usage" covers it as long as you give some indication of the original copyright holder, as you do. The only time I got stroppy about it was when a fellow blogger nicked the photo of Sanity off the front page of the blog and used it on her own, without acknowledgment. I think it's the only time I've sent a take down request.

[alan_fincher]

Galton tunnel construction.

 

H R Dunkley photograph on the CRT digital archive.

[cuthound]

I guess it depends on what you mean by "pre fabricated"?

 

I think many describe the new section of Blisworth as being built from pre-fabricated parts, but it of course does not mean that 3/4 mile of tunnel was delivered as an already completed part.

 

Surely the tunnels near Galton are simply too large that they could have been brought there as already cast "tubes"?

 

I still think that, like a pre-fabricated house, they wee put together on site from pre-fabricated parts.

 

There must be pictures of the construction, but I'm damned if I can now find one!

Best I can find are these, but they don't show the method of construction.

 

http://www.tonycanalpics.co.uk/bcn/mainline/galton.jpg

 

http://www.tonycanalpics.co.uk/bcn/mainline/galt.jpg

[alan_fincher]

Best I can find are these, but they don't show the method of construction.

 

http://www.tonycanalpics.co.uk/bcn/mainline/galton.jpg

 

http://www.tonycanalpics.co.uk/bcn/mainline/galt.jpg

 

See post above!

[PaulG]

Galton tunnel construction.

 

H R Dunkley photograph on the CRT digital archive.

Looks as if it's reinforced concrete, cast in situ using plywood and timber shuttering.

[alan_fincher]

Looks as if it's reinforced concrete, cast in situ using plywood and timber shuttering.

Yes to my untrained eye it does look more acst in situ than in any way prefabricated.....

 

 

(From Wikimedia Commons, the free media repository)

[alan_fincher]

A picture where the colours have become highly compromised over the years, but what it looked like when we approached it shortly after construction.

 

[David Mack]

Galton and Summit Tunnels were cast in situ. I remember the long stoppages of the Old and New Main Lines (but not at the same time) to allow the construction to take place. Its a shame the Galton Tunnel didn't include the second towpath. When first built there was a path over each portal to connect to the other towpath, but it was never much used and last time I looked it had disappeared completely into the undergrowth.

 

Shortly after the tunnels were built I was told that the tunnels with massive infill above had been found to be the cheapest option during design. But by the time they were built we had the 1973 oil crisis and the fuel cost of hauling all that fill meant that a high level long span bridge would have been cheaper!

 

The central section of Blisworth Tunnel was built of precast concrete segments, constructed into rings within the tunnelling shield. There is a complete ring set into the cutting slope by the south portal.

 

Edited March 18, 2016 by David Mack

[cuthound]

Great photos from the CRT archive. So it would appear no prefabrication at all.

 

Obviously I didn't recall correctly.

 

I believe the Blissworth tunnel sections were constructed to counteract the upward pressure of groundwater, which had buckled the original tunnel base. There is/used to be a display in the museum showing this.

[___]

Well the two new fairly modern structures that enclose the old and new BCN main lines near Galton Bridge are certainly described as "tunnels", and I don't think they are unique in that respect. Isn't the culverted part of the Droitwich that passes under the Motorway also called a tunnel. and I'm sure there are others the same.

One of the odder tunnels these days is surely the one over the lower approach to Tuel Lane lock. From my understanding part of that is probably where one of the two original locks that the new one replaces used to be, (or is that not actually exactly how it works?).

 

Just to clarify I meant that very few tunnels built at the same time as the canal would be cut and cover. Obviously every tunnel built since would be cut and cover just with a century or two between the 'cut' and the 'cover'. As I suspect you know the method of building the original Metropolitan Railway was to dig up the pre-existing road, build the railway down between temporary piles and then cover over once complete to reinstate the road. Not really much call for that sort of thing of canals.

 

I think your examples simply confirm it isn't the means the construction that is the defining factor of what constitutes a tunnel and assume that is your point. The Droitwich example may be both a culvert (which is function of diameter) and a tunnel (which is a function of length).

 

JP

[GreyLady]

I don't know much about canals but those navvy's must of been bloody hard blokes - and women who played a part obviously.

 

I guess a lot of people reep the leisure benefit without thinking of the people who risked / gave their life to make the canals/tunnels/aquaducts and bridges possible ( albeit for transporting goods not leisure )

Edited March 18, 2016 by GreyLady

[AndrewIC]

Wasn't Leek tunnel rebuilt using a kind of cut and cover technique?

[Idunhoe]

Certainly was

[ditchcrawler]

Just to clarify I meant that very few tunnels built at the same time as the canal would be cut and cover. Obviously every tunnel built since would be cut and cover just with a century or two between the 'cut' and the 'cover'. As I suspect you know the method of building the original Metropolitan Railway was to dig up the pre-existing road, build the railway down between temporary piles and then cover over once complete to reinstate the road. Not really much call for that sort of thing of canals.

 

I think your examples simply confirm it isn't the means the construction that is the defining factor of what constitutes a tunnel and assume that is your point. The Droitwich example may be both a culvert (which is function of diameter) and a tunnel (which is a function of length).

 

JP

I thought (but don't have reference) it was the recognised way of what today would be going through a deep catting as it was build by digging a narrow trench, 12 foot ish wide and not sloping sides maybe 100 foot across the top like you need for a cutting.

 

https://canalrivertrust.org.uk/directory/45-foulridge-tunnel

 

1783 http://map.coflein.gov.uk/index.php?action=do_details&cache_name=cG5tcnNuYW1lLGhhZm9kIGNvcHBlcndvcmtzX3NlYXJjaHR5cGUsYWR2YW5jZWQ=&numlink=85093

Edited March 18, 2016 by ditchcrawler

[captain birdseye]

According to an old railway civil engineer, the railway definition of a tunnel is stated as something like ' an overbridge covering more than 50 meters in length along the track'.

[___]

I thought (but don't have reference) it was the recognised way of what today would be going through a deep catting as it was build by digging a narrow trench, 12 foot ish wide and not sloping sides maybe 100 foot across the top like you need for a cutting.

 

https://canalrivertrust.org.uk/directory/45-foulridge-tunnel

 

1783 http://map.coflein.gov.uk/index.php?action=do_details&cache_name=cG5tcnNuYW1lLGhhZm9kIGNvcHBlcndvcmtzX3NlYXJjaHR5cGUsYWR2YW5jZWQ=&numlink=85093

It's really a method for shallow tunnels and where the land above is of value; such as your example of White Rock Tunnel in Swansea. I am surprised that Foulridge would have been constructed by cut and cover as remote land such as lies above it wouldn't have any significant value so why bother reinstating it once the cut had been made? It may have been a condition of the enabling act but that doesn't seem likely since the tunnel is there for geographic rather than aesthetic reasons. The problem with building a deep trench is that the sides will need to be retained and that is expensive compared to battering back the sides so a cutting will still be a more economic solution where land values are low - as would have been the case where and when most original canal tunnels were built. Hence canal tunnels are usually relatively deep and were dug/blasted out from a series of intermediate shafts as per GreyLady's picture. Most tunnels had far more shafts for construction purposes than were retained for ventilation purposes.

 

JP

 

According to an old railway civil engineer, the railway definition of a tunnel is stated as something like ' an overbridge covering more than 50 meters in length along the track'.

Correct. And a viaduct is a bridge with more than 3 spans. But there are anomalies and exceptions and the name of the structure isn't always to be relied upon as being definitive. I note that Wikipedia makes no attempt to define a tunnel other than to note the common feature of tunnels being relatively long compared to their width.

 

JP

Edited March 19, 2016 by Captain Pegg

[Murflynn]

 

According to a quick calculation, if it takes two minutes to get a full length boat through (from the stem entering the tunnel to the arsend emerging) the transit speed is about 0.36m/s or 1.2ft/sec, or if you like, 0.8mph.

 

You could leg the boat through at that speed.

.............. which is of course the preferred modus operandi.

[Graham Davis]

According to an old railway civil engineer, the railway definition of a tunnel is stated as something like ' an overbridge covering more than 50 meters in length along the track'.

 

May have been the way in the past, but not nowadays.

There is certainly no length definition in the Rule Books.

I remember it was something that was asked when I was at Signalling School and no definitive answer could be found.

[___]

May have been the way in the past, but not nowadays.

There is certainly no length definition in the Rule Books.

I remember it was something that was asked when I was at Signalling School and no definitive answer could be found.

 

See post #47 Graham.

[Graham Davis]

Now I wonder why the Instructors at Leeds didn't know that?
And it certainly isn't in the Rule Book; perhaps it ought to be?

Thanks.