On Wed, 9 May 2007, MIG wrote:

On May 9, 7:11 pm, Tom Anderson wrote:

I was wondering, as i was sat on it this morning, whether it would be
possible to construct a connector between the Bank and CX branches
around about Euston, so that they could act as two arms of a loop, with
trains running Kennington - Bank - Euston - Charing Cross - Kennington
and vice versa. Based on what you say, perhaps not.

For the clockwise route, drive a tunnel from the northbound Charing
Cross branch some way south of the platform, drop down to the level
between the two branches, run along under the branch, then dive to join
the southbound Bank branch just 'north' of the platform, perhaps
exploiting the old northbound alignment. For the anticlockwise route,
start your tunnel from the northbound Bank branch at what remains of
the northbound alignment, and is now a reversing siding, to the 'south'
of the platforms; climb over the southbound Bank platform, turn north,
and loop round to join the southbound Charing Cross branch just north
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^
of its platform. Provided there's as much vertical separation between
^^^^^^^^^^^^^^^
the branches as i hope there is, and provided there's nothing awkward
underground to the north of the Bank branch platforms (er, Euston
station itself?), this would avoid some of the major complaints - all
trains to Bank and Charing Cross would go from the same platform
(IYSWIM), and there would be enough track in 'limbo' between the main
routes of the branches to hold a train or two, so helping avoid
head-of-line blocking - rendering this idea merely bad, rather than
terrible.

Wouldn't that mean two separate platforms for trains to Charing Cross
though, depending on whether looping or coming from Camden?

No - see highlighted bit above.

tom

--
Throwin' Lyle's liquor away is like pickin' a fight with a meat packing
plant! -- Ray Smuckles

On 11 May, 23:28, Tom Anderson wrote:
So an Edgware - CX train has managed to delay a Barnet - Bank train.

This is discussed in the Transport 2025 document as the recent they
want to split the line:

"Following the PPP Northern line upgrade, the line will operate 30tph
on the southern Morden to Kennington section, but the branches through
central London will be operating at only 22-25tph and will remain
crowded. The limit on capacity is the need
to inter-work services to different destinations via different
branches."

U

In article , Tom
Anderson writes
I was wondering, as i was sat on it this morning, whether it would
be possible to construct a connector between the Bank and CX
branches around about Euston, so that they could act as two arms of


Not really, since it would have to miss Euston.
Not so! See my previous post with the ramble in it. Or not, if you prefer.

And, if you plot my details (which you quote) on a map, you'll find that
it's perfectly practical to run tunnels westwards from Euston (City)
that link into the CX branch before it reaches Warren Street. Well,
practical in plan; I don't know whether vertical separation would be a
problem or whether there are other issues (as well as cost, of course).

Why "delay-inducing"? The junctions are designed so that all possible
non-conflicting moves can be done simultaneously.
It was my understanding that although the junction is graded, there's
still interference between the lines.
[...]

True. It can be a problem for some combinations.

It's the big-metal-rolly-thing analogue of head-of-line blocking in
network switches, if you've come across that (not that i'm implying
you'd sully your hands with such link-layer trivia ).

Don't! I have a long-running argument going on with BT about SCTP
implementation or, in their case, misimplementation.

--
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:

On Fri, 11 May 2007, Mr Thant wrote:

On 11 May, 23:28, Tom Anderson wrote:

So an Edgware - CX train has managed to delay a Barnet - Bank train.

This is discussed in the Transport 2025 document as the recent they
want to split the line:

"Following the PPP Northern line upgrade, the line will operate 30tph on
the southern Morden to Kennington section, but the branches through
central London will be operating at only 22-25tph and will remain
crowded. The limit on capacity is the need to inter-work services to
different destinations via different branches."

Good cite.

This may also involve Kennington, though, where there's obviously a
slightly simpler kind of interference between the two central branches.
You could avoid it by turning *all* CX trains there, but passengers might
not be happy about this!

tom

--
We got our own sense of propaganda. We call it truth. -- Rex Steele,
Nazi Smasher

A small addition to the thread - I've changed some URLs that I posted
before. To find the map use the main URL (it will remain useful):
http://www.fxfp.com/lib/tube/

This is due to the release of first test version of future extensions
map - only first phase of East London Railway so far (and Regent's
Park :-P ). But I have huge plans - for example I'm preparing
historical map for 22nd Dec 1932 (I wonder if anybody will guess all 5
reasons that made me choose that particular date?).

On 13 May 2007 21:10:46 -0700, alex_t
wrote:

A small addition to the thread - I've changed some URLs that I posted
before. To find the map use the main URL (it will remain useful):
http://www.fxfp.com/lib/tube/

I think the map is really very nice effort - goodness knows how much
work it's taken.

I know you've been subjected to a lot of comments and corrections to try
to get the relative geography of the lines correct. There is one
station where the alignment of lines relative to their interchange is
not right. At West Ham the Jubilee platforms are to the south of the
District / H&C and their platforms are to the east of the Jubilee Line.
Up to you if you wish to make this change or not.

--
Paul C


Admits to working for London Underground!

On Fri, 11 May 2007 07:02:55 +0100, Clive D. W. Feather wrote:

* From north of Harrow-on-the-Hill to north of Moor Park - four tracks:
Southbound Slow
Northbound Slow
Southbound Fast (no platform except at Moor Park; used by Chiltern)
Northbound Fast (no platform except at Moor Park; used by Chiltern)

At Moor Park, the slow lines connect to both Watford and Rickmansworth,
but the fast lines only to Rickmansworth.

Unless I've misunderstood something, according to a recent post
) and thread, there is a connection
from the fast lines to Watford, and it's currently being moved further
south.

On Fri, 11 May 2007 19:12:29 +0100, Tom Anderson wrote:

Were the line split, one presumes that the Charing Cross branch would
be permenently wed to one of the Edgware and Barnet branches, and the
Bank branch wedded to the other one. The station would then
automatically become one that provided a cross-platform interchange
between two north/south lines, much like Finsbury Park. No tunnelling
needed.

Although the present passageway layout wouldn't be able to handle the
amount of interchange traffic that would result. This is one of the main
reasons why the line hasn't been split, and the reason LU have been
pushing their Camden redevelopment masterplan.

I can't help thinking that can't be the real reason. Building a few
new passageways deep underground doesn't require the demolition of
half of Camden and building of a massive shopping centre.

On May 15, 12:00 pm, asdf wrote:
On Fri, 11 May 2007 07:02:55 +0100, Clive D. W. Feather wrote:

* From north of Harrow-on-the-Hill to north of Moor Park - four tracks:
Southbound Slow
Northbound Slow
Southbound Fast (no platform except at Moor Park; used by Chiltern)
Northbound Fast (no platform except at Moor Park; used by Chiltern)

At Moor Park, the slow lines connect to both Watford and Rickmansworth,
but the fast lines only to Rickmansworth.

Unless I've misunderstood something, according to a recent post
) and thread, there is a connection
from the fast lines to Watford, and it's currently being moved further
south.



From the fast Metropolitan, the last connection to Watford requires
crossing to the slow lines at Harrow on the Hill. From the Chiltern
lines I don't think there's any connection to Watford at all without
reversing at Rickmansworth.

That's unless a new crossover been built in the last couple of years.

On May 15, 12:00 pm, asdf wrote:
Unless I've misunderstood something, according to a recent post
) and thread, there is a connection
from the fast lines to Watford, and it's currently being moved further
south.

All trains to Watford need to use the slow lines north of Harrow. The
connection you're thinking of allows trains from the slow lines to get
to Rickmansworth, not the other way round.

U