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)