|
Crossrail tunnelling to start shortly
On 2012\03\15 20:44, allantracy wrote:
If it is 13 years late by your reckoning it was 1994 when it ought to have been approved - but it was not - by a Tory government. The previous study that made as far as a Bill were presented in 1991 to a Tory gov finally rejected in 1994 by a Tory gov. How do you think now then ? Well therein lies the difference Tories said we're not doing it and doing it they did not. New Labour said we are doing it and doing it they did not. The difference we now call spin. Indeed... you can't bore a tunnel without spin. |
Crossrail tunnelling to start shortly
On 2012\03\15 21:03, Denis McMahon wrote:
I wouldn't trust a gps derived position underground even if I could receive the signals - you don't know how much bouncing about it's done getting through the soil, pipes, rocks of various types, cables etc above you, and every signal bounce is a loss of accuracy. GPS is not accurate enough for laying a surface railway, never mind an underground one. |
London Crossrail tunnelling to start shortly
Roland Perry:
Surveying works because light travels in straight lines (or so the Physicists tell us). No, actually, what they tell us is that it travels in straight lines *unless* it's traveling through a non-uniform medium. When the Channel Tunnel was being built, they had to correct the laser-based alignment for the variations in air temperature within the incomplete tunnel. However, I doubt that this would be much of an issue for the rather shorter distances between stations on Crossrail. -- Mark Brader | "The speed of sound is considerably less than the Toronto | speed of light -- that is why some people appear bright | until you hear them talk." My text in this article is in the public domain. |
Crossrail tunnelling to start shortly
In article , Basil Jet
scribeth thus On 2012\03\15 21:03, Denis McMahon wrote: I wouldn't trust a gps derived position underground even if I could receive the signals - you don't know how much bouncing about it's done getting through the soil, pipes, rocks of various types, cables etc above you, and every signal bounce is a loss of accuracy. GPS is not accurate enough for laying a surface railway, Really?. never mind an underground one. How could you receive the GPS signals underground anyway?.. -- Tony Sayer |
Crossrail tunnelling to start shortly
On 15/03/2012 20:44, allantracy wrote:
If it is 13 years late by your reckoning it was 1994 when it ought to have been approved - but it was not - by a Tory government. The previous study that made as far as a Bill were presented in 1991 to a Tory gov finally rejected in 1994 by a Tory gov. How do you think now then ? Well therein lies the difference Tories said we're not doing it and doing it they did not. New Labour said we are doing it and doing it they did not. Providing you ignore all the years of preparatory work that has been going on before they could get to the point of unleashing the TBMs. -- Graeme Wall This account not read, substitute trains for rail. Railway Miscellany at http://www.greywall.demon.co.uk/rail |
Crossrail tunnelling to start shortly
On 15/03/2012 20:53, Arthur Figgis wrote:
On 15/03/2012 20:48, Bruce wrote: wrote: On Mar 15, 10:53 am, Mizter wrote: Tunnel boring So, it's finally really happening. Most days I travel one way or the other through Paddington on the Hamcity& Mersmith line and I've been watching the machinery being assembled bit by bit. Its impressive kit. I don't recall the channel tunnel machinery being as impressive but maybe grey cells are decaying. The Channel Tunnel machinery was crude and simplistic on the British side, but extremely sophisticated and impressive on the French side. The British tunnelling engineers laughed at the French machines, Which engineers, and how do you know that they did? It doesn't seen the sort of thing that engineers (real engineers, rather than repairmen or shopkeepers) who I've come across would do, as most seem to find different approaches to specific problems to be quite interesting. You forget that Polson was Morton's right hand man on the project and therefore knows everything about it. -- Graeme Wall This account not read, substitute trains for rail. Railway Miscellany at http://www.greywall.demon.co.uk/rail |
Crossrail tunnelling to start shortly
On Mar 15, 9:38*pm, allantracy wrote:
Yes, you can always rely on the French to be a bunch of poseurs. Pity they aren’t so good at armies. "According to historian Niall Ferguson, of the 125 major European wars fought since 1495, the French have participated in fifty - more than both Austria (forty-seven) and England (forty-three). And they've achieved an impressive batting average: out of 168 battles fought since 387BC, they have won 109, lost 49 and drawn 10." (From 'The Second QI Book of General Ignorance', funnily enough). ---- Colin Williams. |
Crossrail tunnelling to start shortly
In message , at 00:48:37 on
Fri, 16 Mar 2012, Basil Jet remarked: I wouldn't trust a gps derived position underground even if I could receive the signals - you don't know how much bouncing about it's done getting through the soil, pipes, rocks of various types, cables etc above you, and every signal bounce is a loss of accuracy. GPS is not accurate enough for laying a surface railway, never mind an underground one. It's accurate to about 10cm (if you employ differential GPS) which probably good enough for avoiding a 10m obstacle 40m underground. Obviously, you don't use it to measure the distance between the rails when you are laying the track. -- Roland Perry |
Crossrail tunnelling to start shortly
On 16/03/2012 10:10, Paul Corfield wrote:
On Fri, 16 Mar 2012 08:34:43 +0000, Graeme Wall wrote: On 15/03/2012 20:44, allantracy wrote: If it is 13 years late by your reckoning it was 1994 when it ought to have been approved - but it was not - by a Tory government. The previous study that made as far as a Bill were presented in 1991 to a Tory gov finally rejected in 1994 by a Tory gov. How do you think now then ? Well therein lies the difference Tories said we're not doing it and doing it they did not. New Labour said we are doing it and doing it they did not. Providing you ignore all the years of preparatory work that has been going on before they could get to the point of unleashing the TBMs. Goodness are you telling me that design, statutory approvals and consultation, property purchase, procurement, utility works and mobilisation didn't all happen in the last couple of months? I'm shocked. I thought Justine Greening had been doing it all single handedly. I'm sure Boris will claim it was all his doing. -- Graeme Wall This account not read, substitute trains for rail. Railway Miscellany at http://www.greywall.demon.co.uk/rail |
| All times are GMT. The time now is 12:58 PM. |
Powered by vBulletin®
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2006 LondonBanter.co.uk