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Old May 22nd 12, 08:56 PM posted to uk.railway,misc.transport.urban-transit,uk.transport.london
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Default BML2/Crossrail Western Extensions.

On May 22, 8:24*pm, (Mark Brader) wrote:
During WW2 a start was made on a main line gauge tube paralleling the
Northern line,
Details? *First I've heard of such a scheme. *There was the deep level
express lines, tube gauge tunnels bypassing Northern line stations
with the idea of introducing skip-stop type working, but that was a
pre-war plan and definitely not main line sized.


The Northern line *had* skip-stop working before the war.

This was a WW2 program. *The idea being that during hostilities the
tunnels would be utilized as bunkers. *I believe there are surface
buildings visible along the Charing Cross branch.

Doing a bit of googling suggests this is the same scheme, namely one
to build a bunch of underground bunkers,


This is correct.

which aquired a variety of urban-legend type peacetime justifications.


Not an urban legend. *The bunkers were positioned so that *if* it was
decided to build a main-line gauge express line, *then* they could be
joined up as part of the tunnel.

None of the justifiations seems to stack up particularly well. *If
the plan was for a mainline sized Northern line parallel, then why
were the tunnels only built at stations


I've always assumed it was so that access could be provided through the
existing stations if desired.

(and then not all stations)?


Obviously they were built only at locations where there wouldn't be
stations on the express line. *And the number built was only as many
as were needed or could be afforded.

And why were some also built on the Central line?


Presumably shelters were needed there also.

If the plan was to allow for express services on the Northern line,
why were the tunnels built to a larger-than-tube sized bore?


To allow for a separate express route with main-line size trains,
as stated.

The only explanation that makes sense to me is that the plan was
to build some bunkers, in locations that were accessible (because
of the existing stations), with no particular plan beyond that.


And the authors of "Rails Through the Clay" were taken in by an
urban legend? *I don't think so.


Thank you Mark.