The restriction presumably arises from the introduction of 'A' stock on the
East London line.

This has a somewhat wider loading gauge than normal sub-surface stock, and
is not normally operated east of Aldgate.

"David Splett" wrote in message
...
"Sharon & Gordon Thomson" wrote in
message ...
Has its use always been restricted to one train in one
direction at a time because of tight clearance?

No. This restriction appears to date from approximately the time of the
East
London Line Closure. I can't remember if it was just before, during or
just
after.


Has anyone on the group
travelled it over it?

Yes; last year's East London Explorer railtour, operated by Cravens
Heritage
Trains, ran over it in both directions. I have also seen material which
suggest that football specials from Surrey Quays have taken passengers
over
it; I've no idea what (if) that ceased happening.

"Gunslinger" wrote in message ...
The restriction presumably arises from the introduction of 'A' stock on the
East London line.

This has a somewhat wider loading gauge than normal sub-surface stock, and
is not normally operated east of Aldgate.

People keep mentioning how wide A stock is , but according to my LU
rolling
stock book , A stock is 9 foot 8 inches wide whereas C stock is 9 foot
7 inches
wide (and that apperently can go anywhere on the sub surface lines) so
we're only talking half and inch either side. I can't believe the
clearances are so tight
in some of these tunnels than 0.5 inch makes a difference! There must
be some
other reason.

B2003

Boltar wrote:
"Gunslinger" wrote in message
...
The restriction presumably arises from the introduction of 'A'
stock on the East London line.

This has a somewhat wider loading gauge than normal sub-surface
stock, and is not normally operated east of Aldgate.

People keep mentioning how wide A stock is , but according to my LU
rolling stock book , A stock is 9 foot 8 inches wide whereas C
stock is 9 foot 7 inches wide (and that apperently can go anywhere
on the sub surface lines) so we're only talking half and inch either
side. I can't believe the clearances are so tight in some of these
tunnels than 0.5 inch makes a difference! There must be some other
reason.

You have to draw the line somewhere in defining the maximum width of
train that can safely negotiate a tunnel, making due allowance for body
roll, track imperfections, etc. If C stock is at that limit for a
particular line, then anything wider, even if it's only an inch wider,
will not be permitted.

In practice it's not just overall static width that's involved; you have
to work with the dynamic envelope. Other factors, such as the length of
each car, the distance between the bogies, the overhang at each end
beyond the bogie, and the minimum curve radius on the line, all affect
whether there is safe clearance.
--
Richard J.
(to e-mail me, swap uk and yon in address)

In article , Richard J.
writes
People keep mentioning how wide A stock is , but according to my LU
rolling stock book , A stock is 9 foot 8 inches wide whereas C
stock is 9 foot 7 inches wide (and that apperently can go anywhere
on the sub surface lines) so we're only talking half and inch either
side. I can't believe the clearances are so tight in some of these
tunnels than 0.5 inch makes a difference! There must be some other
reason.

You have to draw the line somewhere in defining the maximum width of
train that can safely negotiate a tunnel, making due allowance for body
roll, track imperfections, etc.

I believe the actual problem is that A stock is significantly wider at a
different vertical location. Loading gauges aren't just an overall
height limit and a width; they're a complete shape that the train has to
fit into.

Imagine a train that is exactly the same maximum width and height as a
1992 Tube Stock train, but that is rectangular in cross-section. This
train won't fit in the Central Line tunnels - the top corners won't fit.

--
Clive D.W. Feather | Home:
Tel: +44 20 8495 6138 (work) | Web: http://www.davros.org
Fax: +44 870 051 9937 | Work:
Please reply to the Reply-To address, which is:

"Clive D. W. Feather" wrote in message ...

I believe the actual problem is that A stock is significantly wider at a
different vertical location. Loading gauges aren't just an overall
height limit and a width; they're a complete shape that the train has to
fit into.

I guess that begs the question of why A stock was given a profile that they knew
would not fit in some of the sub surface tunnels. After all , the underground was
well and truly integrated in the 60s so it wasn't because the met line was still
a seperate competing railway, and London Transport had no way of knowing where
the trains might be needed in 20 or 30 years. Seems a strange design decision to
make to me.

B2003

"Boltar" wrote in message
om...

I guess that begs the question of why A stock was given a profile that
they knew
would not fit in some of the sub surface tunnels. After all , the
underground was
well and truly integrated in the 60s so it wasn't because the met line was
still
a seperate competing railway, and London Transport had no way of knowing
where
the trains might be needed in 20 or 30 years. Seems a strange design
decision to
make to me.

By that token one could then also equally argue why did they give the D78
stock the profile that it has, knowing that it will not fit around the west
side of the Circle Line, requiring C69/77 stock to be used on District line
Wimbleware services.

Truth is, the A60/62 stock was built for the Metropolitan main line
(Aldgate - Amersham/Watford/Uxbridge) and for no other purpose and was
designed accordingly, in the same way as the D78 stock was designed for the
Upminster - Ealing Broadway/Richmond/Wimbledon routes. It was only a later
decision to use some spare A60/62 stock on the ELL.

The idea of common stock is only really coming about with the replacements
for A/C/D stock. We shall see just how appropriate it is to have stock
capable of high-density use on the Circle and low-density use on the Met
main line in years to come. Perhaps we will then be arguing about how
unsuitable the stock is on one or other of the lines because it was not
purpose-built for the line in question?

"Jack Taylor" Jack @Carney.co.uk wrote in message k...
"Boltar" wrote in message
om...

I guess that begs the question of why A stock was given a profile that
they knew
would not fit in some of the sub surface tunnels. After all , the
underground was
well and truly integrated in the 60s so it wasn't because the met line was
still
a seperate competing railway, and London Transport had no way of knowing
where
the trains might be needed in 20 or 30 years. Seems a strange design
decision to
make to me.

By that token one could then also equally argue why did they give the D78
stock the profile that it has, knowing that it will not fit around the west
side of the Circle Line, requiring C69/77 stock to be used on District line
Wimbleware services.

Well quite.

main line in years to come. Perhaps we will then be arguing about how
unsuitable the stock is on one or other of the lines because it was not
purpose-built for the line in question?

Its quite easy to build a number of variations that all have the same loading
gauge and profile but perhaps different numbers of doors and internal layout
for the different types of routes they'll run. IMO building a train that won't
physically fit on a large portion of your network is at best short sighted and
at worst just plain bloody stupid.

B2003

In article ,
Boltar wrote:

People keep mentioning how wide A stock is , but according to my LU
rolling
stock book , A stock is 9 foot 8 inches wide whereas C stock is 9 foot
7 inches
wide (and that apperently can go anywhere on the sub surface lines) so
we're only talking half and inch either side. I can't believe the
clearances are so tight
in some of these tunnels than 0.5 inch makes a difference! There must
be some
other reason.

How long are they both overall, and where are the bogie centres ?
Can't find my own stockbook, but that could make a big difference to
how far they swing out on curves. And the restriction does only apply
on St. Mary's Curve, which is noted for being tight.

Nick
--
"My objective at this stage was to work about 3 days per week"
-- Richard Parker in http://web.ukonline.co.uk/richard/cv78.html

"Boltar" wrote in message
om...

according to my LU rolling stock book ,
A stock is 9 foot 8 inches wide whereas
C stock is 9 foot 7 inches wide (and that
apperently can go anywhere on the sub
surface lines) so we're only talking
half and inch either side. I can't believe the
clearances are so tight in some of these
tunnels than 0.5 inch makes a difference!
There must be some other reason.

Not necessarily. If you imagine 121 different trains of varying widths from
9 foot 7 to 10 foot 7, with each one being 1/10th of an inch wider than the
previous, the difference between the widest that will fit and the narrowest
that won't fit must be be 1/10th of inch.

--
John Rowland - Spamtrapped
Transport Plans for the London Area, updated 2001
http://www.geocities.com/Athens/Acro...69/tpftla.html
A man's vehicle is a symbol of his manhood.
That's why my vehicle's the Piccadilly Line -
It's the size of a county and it comes every two and a half minutes