Apologies if this question has been asked/answered before. I was curious as
to why, on the Northern line's city branch, the platforms at Bank and London
Bridge are "reversed". i.e., why do the running lines swap sides during this
stretch?

Many thanks,

Daniel.

Heliomass wrote:
Apologies if this question has been asked/answered before. I was
curious as to why, on the Northern line's city branch, the platforms
at Bank and London Bridge are "reversed". i.e., why do the running
lines swap sides during this stretch?

Many thanks,


In most places the early deep level lines were built under the road. In
order to stay under the road through a tight bend or corner the tunnels swap
from side to side to ease the curve for the trains allowing a higher speed
to be maintained.

"Heliomass" wrote in message
...
Apologies if this question has been asked/answered before. I was curious as
to why, on the Northern line's city branch, the platforms at Bank and London
Bridge are "reversed". i.e., why do the running lines swap sides during this
stretch?

There was long thread on this subject some months ago.

People tried to think of all the places where this happened.

IIRC there's another one on the Central line.

tim



Many thanks,

Daniel.

"tim" wrote in message ...
"Heliomass" wrote in message
...
Apologies if this question has been asked/answered before. I was curious as
to why, on the Northern line's city branch, the platforms at Bank and London
Bridge are "reversed". i.e., why do the running lines swap sides during this
stretch?

There was long thread on this subject some months ago.

People tried to think of all the places where this happened.

IIRC there's another one on the Central line.

The Caxton Curve. It's the shaprest curve on the entire system,
because it follows Caxton Road above it. It's part of a particularly
complex and messy track layout between White City and Shepherds Bush -
the presence of the old single-loop Wood Lane station and the old Wood
Lane depot caused lots of fun when the line was extended past White
City. You can read about it on Hywel William's excellent Undeground
site, http://www.starfury.demon.co.uk/uground/woodlane.html

I have been on the Caxton Curve, which contains the westbound Central
Line, and it is indeed quite sharp - the trains dislike it quite a lot
;-)


tim



Many thanks,

Daniel.



Brad

On Tue, 20 Jan 2004 21:12:07 +0100, "tim"
wrote:



IIRC there's another one on the Central line.


The lines swap vertically between Chancery Lane and St Pauls, IIRC.
What is the reason for this?

... why, on the Northern line's city branch, the platforms at Bank
and London Bridge are "reversed". i.e., why do the running lines
swap sides during this stretch?

In most places the early deep level lines were built under the road.

True, but I have not seen it suggested that that was the issue here.
It doesn't seem plausible to me. The line left the original terminus
at King William Street heading west and curving south under what is
now Arthur Street; this section *was* constrained by the width of the
road and had one tube under the other. They spread apart to the usual
side-by-side arrangement, but reversed, where they emerged from the
street to pass under the river. So there doesn't seem to be anything
in the layout there that would make the reversed arrangement more
attractive.

And the other end of the reversed section was where it is now, between
Elephant & Castle and Borough; the line runs under Newington Causeway,
which I've never visited at street level, but on the map it looks
near enough to straight, so there seems nothing to make a crossing-
over desirable there also.

As to the actual reason that the lines cross over, I don't know it.
My books are silent on the topic except for one, "Rails Through the
Clay", where there is only a vague statement that it was "related to
the original intention to use cable haulage". The original line was
authorized in two sections, north and south of Elephant & Castle, and
these were to have been built with separate cables (running faster on
the straighter south half) until the decision to use electric trains.
Maybe the crossed-over layout would have made it easier to lead the
cables into the tunnels (in the area where they cross over, rather
than at E&C station itself) somehow; but that's only a guess.
--
Mark Brader "Well, it's not in MY interest -- and I represent
Toronto the public, so it's not in the public interest!"
-- Jim Hacker, "Yes, Minister" (Lynn & Jay)

My text in this article is in the public domain.

IIRC there's another one on the Central line.

The Caxton Curve. It's the shaprest curve on the entire system,
because it follows Caxton Road above it. ...

In brief, the tracks cross over here because this single-track curve,
originally built for depot access and not as part of a running line,
was incorporated into the through line when it was extended. The
way it was aligned, it could only become part of the westbound track,
and an even sharper curve would've been needed on the eastbound if
they hadn't been allowed to swap sides instead. Originally a loop
track was used, and when the line was extended further, the tracks
were made to swap back over at a junction (which no longer is one)
north of White City.
--
Mark Brader, Toronto | "Whatever you are, be out and out,
| not divided or in doubt." -- Brand (Ibsen)

My text in this article is in the public domain.

The lines swap vertically between Chancery Lane and St Pauls, IIRC.
What is the reason for this?

This one *is* due to a narrow street above.
--
Mark Brader I "need to know" *everything*! How else
Toronto can I judge whether I need to know it?
-- Lynn & Jay: YES, PRIME MINISTER

"Mark Brader" wrote in message
...

The lines swap vertically between
Chancery Lane and St Pauls, IIRC.
What is the reason for this?

This one *is* due to a narrow street above.

I don't understand, since the do-si-do clearly occupies a larger footprint
than would two tunnels running above each other.

--
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

"John Rowland" wrote in message ...
"Mark Brader" wrote in message
...

The lines swap vertically between
Chancery Lane and St Pauls, IIRC.
What is the reason for this?

This one *is* due to a narrow street above.

I don't understand, since the do-si-do clearly occupies a larger footprint
than would two tunnels running above each other.

I think it's the cathedral and the burial sites surrounding it - I
think the folks who built the original Great Central London Railway
stacked the tunnels because the authorities at St. Paul were afraid
that the digging might disturb or destroy the various gravesites
around the cathedral.

Besides, on the "Continuing your journey from" map, St. Paul's
Cathedral is practically next door to the station - I imagine that the
station builders got enough flak for placing the now-abandoned lift
shafts so close to the cathedral grounds, much less a tunnel.

Brad