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.

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

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

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.

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

So, it's finally really happening.


....... and only thirteen years late.

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?

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

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

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