On Wed, 12 Dec 2007 18:21:33 +0000, Tom Anderson
wrote:

On Wed, 12 Dec 2007, Andy wrote:

On Dec 11, 3:37 am, Mizter T wrote:
On 11 Dec, 00:01, "John Rowland"

wrote:
Mizter T wrote:

That said, it will become a far more critical bit of London's
transport infrastructure when it becomes part of the ELLX, so I guess
it's worth getting everything right first time round during this
closure and making sure all the works are done to a very high
standard.

But this isn't first time around! The ELL was closed for three years not
long ago, when conversion to third rail and use of NR rolling stock etc was
already inevitable.

Yes, I was aware of that though I didn't mention it. One would think
that any major remedial works were done then - the Thames Tunnel was
certainly 'dealt with', though the shotcrete treatment wasn't to the
liking of conservationists, which is of course why the line was closed
for so much longer than originally anticipated (and of course you know
this all already, but I'm just setting the scene for the audience!).

I'd be most interested in seeing a break-down of the works.

One other point to consider is what stock would be operating the line if
it reopened in 9 months (for example) time? Don't forget that the
conversion to National Rail standards with 3rd rail electrification
would rule out the use of A-stock

Oh, like how LU stock can't run to Richmond or Watford? I can't see why
there would be any problem putting in an earth-bonded fourth rail to
sustain the service until it becomes fully Overgrounded.

It isn't done with an earth-bonded fourth rail, the fourth rail is
bonded to the traction current return rail which under particular
conditions (e.g. dry weather and train pulling many amps at the far
end from the substation) can be a number of volts away from earth
requiring the signalling circuits to be designed to match (the
substation end was IIRC described in a previous thread by someone with
the relevant experience). Returning to A stock, if it is working in
isolation then it might be easier to do a Sarah Siddons-style
temporary conversion to 3rd-rail.

and there would be no connection back onto the LUL system for major
servicing anyway.

Rubber-wheeled stock transfer ?

I hadn't realised that was happening. Is there a huge problem with doing
occasional stock transfers over NR lines? Apart from the fact that the
route would via Clapham Junction, some maneuvers out West, and the Dudden
Hill branch ...