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Tunnel boring to begin from the Royal Oak portal heading eastwards under
central London. Pictorial: http://www.bbc.co.uk/news/uk-17365934 Video: http://www.bbc.co.uk/news/uk-england-london-17356912 So, it's finally really happening. |
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On Thu, 15 Mar 2012 10:53:04 +0000
Mizter T wrote: Tunnel boring to begin from the Royal Oak portal heading eastwards under central London. Pictorial: http://www.bbc.co.uk/news/uk-17365934 There doesn't seem to be much distance between the 2 bores. Surely they won't be that close the entire route? Looks like it would collapse. B2003 |
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In message , at 10:55:45 on Thu, 15 Mar
2012, d remarked: http://www.bbc.co.uk/news/uk-17365934 There doesn't seem to be much distance between the 2 bores. Surely they won't be that close the entire route? Looks like it would collapse. The tunnel is concrete-lined as the machine moves forward. I'm more interested in them apparently using GPS 38m underground! -- Roland Perry |
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On Mar 15, 11:11*am, Roland Perry wrote:
In message , at 10:55:45 on Thu, 15 Mar 2012, remarked: http://www.bbc.co.uk/news/uk-17365934 There doesn't seem to be much distance between the 2 bores. Surely they won't be that close the entire route? Looks like it would collapse. The tunnel is concrete-lined as the machine moves forward. I'm more interested in them apparently using GPS 38m underground! There distance between the tunnels may not be constant. Does GPS penetrate that far? One is intrigued as to how this works. ISTR earlier tunnels being aligned by laser. The Twenty-first Century is starting with this much needed and really exciting rail project. When the economic recovery comes we see more projects like this. London badly needs them. |
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In message
, at 05:41:17 on Thu, 15 Mar 2012, 77002 remarked: There doesn't seem to be much distance between the 2 bores. Surely they won't be that close the entire route? Looks like it would collapse. The tunnel is concrete-lined as the machine moves forward. I'm more interested in them apparently using GPS 38m underground! There distance between the tunnels may not be constant. No doubt they do spread apart as they get further from the portal. Does GPS penetrate that far? One is intrigued as to how this works. ISTR earlier tunnels being aligned by laser. Surveying works because light travels in straight lines (or so the Physicists tell us). In the old days you peered through a theodolite at poles held by your colleagues. Today, perhaps you shine a laser in the other direction. There's very little difference in the precision (which is all about measuring angles), even if modern methods may be less labour intensive. -- Roland Perry |
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So, it's finally really happening. ....... and only thirteen years late. |
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On 15/03/2012 14:55, allantracy wrote:
So, it's finally really happening. ...... and only thirteen years late. so it is doing better than Thameslink 2000? |
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On Mar 15, 10:53*am, Mizter T 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. -- Nick |
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On Mar 15, 2:55*pm, allantracy wrote:
So, it's finally really happening. ...... and only thirteen years late. It was approved 2007 ... under a Labour government based on the 2005 proposals ... made during a Labour government. 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 ? -- Nick |
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On Mar 15, 7:02*pm, D7666 wrote: On Mar 15, 2:55*pm, allantracy wrote: So, it's finally really happening. ...... and only thirteen years late. It was approved 2007 ... under a Labour government based on the 2005 proposals ... made during a Labour government. 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 ? Quite - here's a very brief historical background on an archived page which used to reside on Crossrail's own website: http://preview.tinyurl.com/8a8funk |
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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. |
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D7666 wrote:
On Mar 15, 10:53*am, Mizter T 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, claiming that they were absurdly complex and would make very slow progress compared to the much simpler machines on the British side. In the final reckoning, the French machines were very reliable and worked faster than expected despite encountering ground conditions that were much worse than expected. Meanwhile, the British machines struggled in better ground that the French had to deal with and proved unreliable and inadequate. The planned meeting point between the British and French tunnel drives had to be moved towards Kent several times (and by significant distances) because the French machines made such rapid progress compared to ours. |
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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. -- Arthur Figgis Surrey, UK |
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On Thu, 15 Mar 2012 11:11:40 +0000, Roland Perry wrote:
In message , at 10:55:45 on Thu, 15 Mar 2012, d remarked: http://www.bbc.co.uk/news/uk-17365934 There doesn't seem to be much distance between the 2 bores. Surely they won't be that close the entire route? Looks like it would collapse. The tunnel is concrete-lined as the machine moves forward. I'm fairly sure the tunnel segments are up to the job, they're probably similar to the chunnel ones, or even the HS1 ones. I'm more interested in them apparently using GPS 38m underground! I expect that's a simple throw away line that means rather less than it sounds. I expect that "navigation" is going to be driven by laser sightings out of the rear of the machines, along the tunnel bores using intermediate survey points, to a datum point outside the tunnel bore. The datum point might be fixed by gps, although for a fixed point where absolute accuracy is needed, I suspect that it will be physically surveyed. Although the co-ordinates of various surveying points will be known, the fact that gps systems can use / display such co-ordinates doesn't mean that other systems that use such co-ordinates are gps, which is what I suspect that someone failed to understand when writing that. 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. Rgds Denis McMahon |
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The Channel Tunnel machinery was crude and simplistic on the British side, but extremely sophisticated and impressive on the French side. Yes, you can always rely on the French to be a bunch of poseurs. Pity they aren’t so good at armies. Mind you, I bet they wouldn’t have needed £17bn to build HS2. |
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On 15/03/2012 11:11, Roland Perry wrote:
In message , at 10:55:45 on Thu, 15 Mar 2012, d remarked: http://www.bbc.co.uk/news/uk-17365934 There doesn't seem to be much distance between the 2 bores. Surely they won't be that close the entire route? Looks like it would collapse. The tunnel is concrete-lined as the machine moves forward. I'm more interested in them apparently using GPS 38m underground! Did they ever choose names for them? |
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On Mar 15, 8:44*pm, allantracy wrote:
New Labour said we are doing it and doing it they did not. Explain. What did they not do ? NO WAY was a project like this ever going to get authorised underway and completed in one term of government. If you really think that you are more in cloud cuckoo land than I thought. there has been an election, but that does not undo what was done before. -- Nick .. |
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allantracy wrote:
Bruce wrote: The Channel Tunnel machinery was crude and simplistic on the British side, but extremely sophisticated and impressive on the French side. Yes, you can always rely on the French to be a bunch of poseurs. Laugh as much as you want, but it seems you can rely on the French to get the job done. Actually, they not only got *their* job done, they bored and lined a lot of the tunnel that was supposed to be built from the English side, so they did quite a lot of *ours* too. If it hadn't been for the ability and efforts of the French, the overall project would have taken much longer to complete and the final cost would have been even further over budget. |
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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. |
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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. |
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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. |
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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 |
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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 |
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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 |
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On 16/03/2012 00:17, wrote: In , (Mizter T) wrote: Tunnel boring to begin from the Royal Oak portal heading eastwards under central London. Pictorial: http://www.bbc.co.uk/news/uk-17365934 "The scheme is currently the largest civil engineering project in Europe." Really? Bigger than the Gotthard Base Tunnel? Video: http://www.bbc.co.uk/news/uk-england-london-17356912 So, it's finally really happening. I thought they were starting on the 21st? I noted the date some time back as it's my younger daughter's birthday. Could be, I haven't come across the 21st date before bit nor have I looked for it either. Crossrail press release from Tuesday (13th March): http://www.crossrail.co.uk/news/press-releases/giant-tunnel-boring-machines-ready-to-start-crossrail-dig Excerpt: ---quote--- Today, the first of eight enormous machines, each 150 metres long and weighing 1,000 tonnes, will begin their journey to the Royal Oak Portal in west London from where, next week, they will start tunnelling 6.4 km (four miles) east to Farringdon via Bond Street and Tottenham Court Road. [...] ---/quote--- |
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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. |
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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 |
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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 |
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In message , at 08:36:36 on Fri,
16 Mar 2012, Graeme Wall remarked: You forget that Polson was Morton's right hand man on the project and therefore knows everything about it. iirc he was involved in one of the rival bids (and unsuccessful) bids to build a bridge instead. -- Roland Perry |
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In message , at 10:25:02 on Fri, 16 Mar
2012, Roland Perry remarked: 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. With an implied "apart from the fact it doesn't work under ground", of course. Obviously, you don't use it to measure the distance between the rails when you are laying the track. -- Roland Perry |
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On Fri, 16 Mar 2012 02:58:13 -0700 (PDT)
Colin Williams wrote: "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." 387BC? Thats pretty impressive given france as a nation didn't even exist until the middle ages. B2003 |
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wrote in message
... In article , (Mizter T) wrote: Tunnel boring to begin from the Royal Oak portal heading eastwards under central London. Pictorial: http://www.bbc.co.uk/news/uk-17365934 "The scheme is currently the largest civil engineering project in Europe." Really? Bigger than the Gotthard Base Tunnel? Rule 1. PR departments must exaggerate. They probably believe they are tunneling from Maidenhead to Shenfield AND from Heathrow to Abbey Wood. Then they'll double that figure as there are two tracks. Also see the regular references to the 48 tph train service.... Paul S |
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In message , at 19:17:39
on Thu, 15 Mar 2012, remarked: "The scheme is currently the largest civil engineering project in Europe." Really? Bigger than the Gotthard Base Tunnel? iirc the cost of the tunnel (and perhaps stations) under London is only one third of the total project spend. So to some it extent it depends how much of the project you include. -- Roland Perry |
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On 16/03/2012 10:34, Roland Perry wrote:
In message , at 08:36:36 on Fri, 16 Mar 2012, Graeme Wall remarked: You forget that Polson was Morton's right hand man on the project and therefore knows everything about it. iirc he was involved in one of the rival bids (and unsuccessful) bids to build a bridge instead. Difficult to disentangle all his myriad claims but IIRC he was allegedly working on the tunnel project but thought the bridge proposal was a better option. -- Graeme Wall This account not read, substitute trains for rail. Railway Miscellany at http://www.greywall.demon.co.uk/rail |
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On Mar 16, 10:59*am, wrote:
387BC? Thats pretty impressive given france as a nation didn't even exist until the middle ages. B2003 Perhaps it should have said France and its predecessors. "387 B.C. Battle of Allia. The outnumbered Gauls, led by Brennus, defeat the army of the Roman Republic led by Quintus Sulpicius and ultimately go on to sack Rome itself. " http://www.militaryfactory.com/battl..._victories.asp (Massively off-topic, apologies). ---- Colin Williams. |
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On Mar 16, 7:49*am, furnessvale wrote:
On Thursday, March 15, 2012 10:53:04 AM UTC, Mizter T wrote: Tunnel boring to begin from the Royal Oak portal heading eastwards under central London. So, it's finally really happening. I'm keeping my fingers crossed and mouth shut. *How many false starts did the Channel Tunnel have that actually involved tunnelling underway? Several of the Crossrail stations have been under construction for some time. The ramps down to the portals at Paddington are substantial. Moreover, IIRC, the cost of Crossrail has reduced slightly. |
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On Mar 16, 9:58*am, Colin Williams
wrote: 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). France is one of the Western European countries today that has an effective military. The UK is under defended. |
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Basil Jet wrote:
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. Differential GPS is. This isn't your car's satnav, nor your hand-held Garmin that you take when hiking, it is an extremely precise method of establishing position with great accuracy using highly sophisticated corrections of GPS satellite transmissions. It also takes time to do; your car satnav or hand held GPS receiver gives you a near instant fix to within a few metres, but differential GPS takes hours* to give an accuracy of millimetres. But GPS isn't much use down a tunnel. You can establish precise positions at the shafts using GPS, but you need traditional methods from then on in. [*When I was last personally involved in the late 1990s, it took a couple of days. I am assuming it has gotten quicker in the last fourteen or fifteen years.] |
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