New BBC series about Crossrail

Well I thought that the first episode was pretty interesting. Very impressive that they managed to pass through the eye of the needle without any calamity. Out of interest, what were the tolerances like when they were building the original tubes? With crossrail it was to within a couple of centimetres of the intended route I doubt that the old tube diggers could have been that accurate!

domh245 - I recently watched the Tunnel Vision clip on www.forgottenrelics.co.uk/tunnelvision/index.html, which very interestingly detailed the method by which the alignment and progress of one Victorian tunnel was done - it claims 3" accuracy over a kilometre or so IIRC, using just line of sight towers above ventilation shafts. Pretty darn impressive I'd say. Obviously Tube tunnels deal with a much different above ground geography and underground geology, but the shorter distances between stations may have made the tunneling a bit more accurate.

Its a shame they didn't include more technical stuff

Sounds like a very interesting series tow atch when I get a chance to at some point this week.

It had to withstand the weight of the clay that they removed and replaced with concrete, air and TBM.

From the diagrams they gave - it was 35 cm beneath the foundations for the escalators, so that would have been sufficient clearance. Likewise 85cm above the tunnels would be sufficient clearance, as the weight of the TBM will have be spread out over a fair area, don't forget that as soon as the tunneling head has gone, the walls are sprayed with concrete to harden the mud around it, before the concrete linings are put in place.

Thanks for the Victoria line film, that's really interesting, sadly, more watchable than the new documentary shown on Wednesday for me.

It was one of those "put a camera in front of someone and they turn into an idiot" sort of programme ... the people with "Where's Willy?" (the hours must fly by for them), the berk supervising the crane removal, all the usual reality show types were there.

There were a couple of interesting things in it, the damage being caused to the building in Soho Square was a high point, but all the drama about threading the needle just led to a "well that worked" result. Which of course should have been the outcome but doesn't make for interesting telly. I'm hoping the next episode is better.

Just some comments on the second and third episode.

I found it really interesting how close the Connaught Tunnel was to the bottom of Royal Albert and Victoria docks and how they had to block it off and rebuild the tunnel in such a short time span.

For the final episode, I am disappointed that whilst it was a treat seeing the TBM break through at Whitechapel, they did not show anything else at that station. The archaeology throughout was good however..

Hmmm, interesting they never mentioned the construction of Woolwich which if I'm correct will be the only completely brand new station with no interchange. I know Canary Wharf is the other one but it does have surface level interchange.