Dulnain Bridge Strathspey Rly

http://www.railstograntown.org/page.php?domain_name=railstograntown.org&viewpage=news

The replacement bridge is due to be installed in Feb. I hope they post lots of photos HERE.

 

They really have great ambition there don't they ? A real 'no job too big' attitude. The list of participating organisations giving their time and materials for free is so impressive its clear that the Strathspey has some great organisers in their midst. Like Philw2 says, I hope they do post up loss of photos as having stood by that river, this is no small project. The bridge will look terrific once its complete.

 

I agree the bridge will be an impressive addition. Unless I'm mistaken, the tunnel under the A95 will be a first in standard gauge preservation and therefore, I suggest, more impressive in engineering terms yet not nearly so conspicuous.

 

I suspect the tunnel will be a cut-and-cover job with an in-situ reinforced concrete box culvert forming it and the road realigned and raised by filling with suitable material over it. The box may have precast concrete roof panels instead of an in-situ arrangement..

 

Quite possibly so; unlike the bridge span they would have some difficulty reusing a redundant tunnel from elsewhere.

 

A couple of railway 'tunnels' under roads have used Armco for this - basically heavy gauge corrugated sheet steel in the form of a circular tube - and is is generally much cheaper than conventional tunnels, especially where it is built as cut and cover work. It only takes a couple of days to build, as well.

 

It may be slightly more substantial than anticipated. If I remember correctly there is a requirement for the tunnel to take both the railway and a local access road so that vehicles don't have to cross the A95 as they currently do. I guess it all depends upon funding though.

 

Dunno but the one taking the Middleton Railway under the M621 was built in 1971 and shows no obvious signs of deterioration, other than a crack in a concrete wing wall (which has been there almost as long as the tunnel). I don't know if the steel is galvanised or not but is covered in a thick layer of bitumen like material.

 

Here's another cut-and-cover method..

http://en.wikipedia.org/wiki/Gerrards_Cross_Tunnel

 

A number of the bridges on the reinstated Welsh Highland are of the Armco variety I believe.

 

That one didn't make it to the completion date before failing!.

 

Not an Armco one, though.

 

The RAIB report sugested bad building rather than bad design. Basically you fill the gap at the bottom first to stop the sides moving - then add spoil to the top - the oposite to Gerard getting very Cross.

 

The Colas-owned 120 tonne Kirow crane reported taken to Scotland by 56078 for tomorrow's big lift of the aforementioned bridge.

Perhaps worth keeping an eye on the website for some images?

link: http://www.railstograntown.org and have a look at the "news" page I assume.

46118

 

First beam going in. Picture on Facebook
https://www.facebook.com/Strathspey.Trains?fref=ts

 

Also: http://www.bbc.co.uk/news/uk-scotland-highlands-islands-26191444

 

That crane is ine serious bit of kit. Each girder must be quite a few ton. The crane did however remind me of a rail mounted gun.

 

Congratulations to them for getting the job done.

However they had it easy.
When we did it on the NYMR, No vehicle access for miles, 1 in 49 gradient and loads and loads of snow.
Look at the newsclip from Dulnain and they can drive vans alongside in the field.