Box tunnel pushed under railway nr Peterborough

[saaby93]

Anyone have a better video than this showing what they were pushing it under and how that was supported?
https://www.bbc.co.uk/news/av/uk-england-cambridge...
Why the musak

[Flying Phil]

I think this technique has been used before. I'm sure the second tunnel for the A43 went under the M1 in a similar manner way back in the 1990's?

[RyanOPlasty]

This technique has been used before, but I don't think it has been done on a curved tunnel or one so long in this country.

[Simpo Two]

saaby93 said:

Why the musak

Because captions and musak are cheaper than a VO and easier to do.

[mcdjl]

saaby93 said:

Anyone have a better video than this showing what they were pushing it under and how that was supported?
https://www.bbc.co.uk/news/av/uk-england-cambridge...
Why the musak

Becuase its the BBc and they assume that people
A) wont look at anything not accompanied by a video
b)can't read anything unless its on a video
c) can't watch a video (or do anything) unless accompanied by awful musak.

[saaby93]

mcdjl said:

saaby93 said:

Anyone have a better video than this showing what they were pushing it under and how that was supported?
https://www.bbc.co.uk/news/av/uk-england-cambridge...
Why the musak

Becuase its the BBc and they assume that people
A) wont look at anything not accompanied by a video
b)can't read anything unless its on a video
c) can't watch a video (or do anything) unless accompanied by awful musak.

and why is it compared the eiffel tower
Why not the size of Wales

[mcdjl]

saaby93 said:

and why is it compared the eiffel tower
Why not the size of Wales

It should be nelsons column, double decker buses, or elephants.

[normalbloke]

mcdjl said:

saaby93 said:

and why is it compared the eiffel tower
Why not the size of Wales

It should be nelsons column, double decker buses, or elephants.

But how many Pringles tubes is that?

[MinionBob]

normalbloke said:

But how many Pringles tubes is that?

55 million

[Chrisgr31]

saaby93 said:

Anyone have a better video than this showing what they were pushing it under and how that was supported?
https://www.bbc.co.uk/news/av/uk-england-cambridge...
Why the musak

The answer is it wasn’t pushed under at all! There are some great videos on the Network Rail Twitter feed on how they did this. They basically moved 2 small tunnels parallel to each other under the railway. In each of the tunnels they laid a rail. In the meantime next to the line they built a huge concrete 3 sided box (2 walls and a roof there was no floor) the walls of which were sitting on an extension to the mentioned rails. The base of the box as built was a totally separate concrete pad, with what you might call gouges in the floor.

When the tunnels were complete and the box ready they closed the railway and dug a box shaped hole in it. They then used rams which were secured against the gouges in the concrete pad to push the box along the rails. Until it filled the gap in the railway above. They then relaid the railway above the box and reopened it. They can continue working in the box to lay the new line that goes under it.

I have forgotten how long the line over the top was closed for - maybe a long weekend. Under traditional methods it would have been closed for months whilst they dug out the line, built the walls for a bridge, build a bridge deck then relaid the railway above.

[xx99xx]

Similar thing, albeit smaller scale, with construction of Jubilee River (Maidenhead): https://en.m.wikipedia.org/wiki/Jubilee_River.

They froze the embankment, dug it away and pushed in some pre cast concrete culverts, all underneath a main line rail and the M4 fully open.

[Ian Lancs]

normalbloke said:

mcdjl said:

saaby93 said:

and why is it compared the eiffel tower
Why not the size of Wales

It should be nelsons column, double decker buses, or elephants.

But how many Pringles tubes is that?

What about Olympic size swimming pools?

[DanMalkin]

'Similar' system to the Autoripage system that Osborne utilised in October 2002 to slide the Shortland Junction box into place. Very interesting scheme to be involved in and at the time it was the longest box push ever attempted.

It's great as a Civil Engineer in Railways to see innovation in the Rail Sector. We've traditionally ben forced to follow established practices rather than embrace new technologies.

However - I still love working on historic structures! Looking forward to Barmouth Timber Viaduct Phase 2 in September 2021