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.

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.

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.

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

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

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

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---

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.

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

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