On Apr 14, 8:46*am, wrote:
On Apr 13, 4:59*pm, MIG wrote:





On Apr 13, 2:03*pm, Tom Anderson wrote:

On Mon, 13 Apr 2009, MIG wrote:
On Apr 13, 12:14*pm, Tom Anderson wrote:

Been reading the last issue of London Loop. In an article about work on
the Northern line, it says:

* There will be more trains too - making a total of 24 on the central and
* northern branches, and 32 on the Morden section.

Do they mean trains, or trains per hour? Or something else? And is that 24
on each branch, or between the two? I'm guessing the latter and the
former, respectively!

Are these the improvements that are due to resignalling but being
attributed to splitting the line in order to justify the inconvenience
caused by that, but then attributed to the signalling as well to justify
the disruption caused by the signalling work, thus having all cakes and
eating them?

I don't know, but now i want cake.

Are you suggesting that with the new signalling, the line could be run
un-split and be as frequent and reliable as in the split case?

Probably as reliably as now anyway and certainly as frequent. *I think
that the split is a case of the common tactic of reducing the service/
convenience in order to get browny points for "punctuality" (because
it takes less effort to run it on time). *But the signalling allows
for some compensation in increased tph.

I am pretty certain that the increased tph is due to the signalling
rather than the split, and that the movements are equally disruptive
whichever pair of branches is involved.

The gain will be in not having to deal with services from both
northern branches going different ways at the junctions south of
Camden Town.

Some increased slack for punctuality in the overall service may result
from the split, ie delays from one branch not affecting both branches
the other side of Camden. *I can't see that that has anything to do
with tph.

If there is a full split in service, for example, with the High Barnet
branch only serving the Bank route and the Edgware branch only serving
the Charing Cross route, then it will be possible to operate more
services through Camden without changing the signalling, as you don't
have to wait for point movement and locking between each train.

I can't see this making any difference. Points would be changed while
the next train was standing in the station, given that it couldn't get
in till the previous one had left anyway.

(In fact it might even allow more tph in that a train going a
different way at a junction doesn't have to wait for the previous one
to clear the section.)

There are no flat junctions to consider whichever way they go, so a
few seconds changing the points while a train is in the station can't
really make any difference to tph.

The split may affect reliability, but I don't believe it can affect
tph.

Increased tph will, however, be offered as a mitigating factor when
people complain about the split.