Tom Anderson wrote:

What i don't get is why the off-peak pattern runs all through trains to
Bank, reversing *everything* from CX. There, the density of trains is much
lower, so the track issue is surely irrelevant - even with the awkward
layout, you could surely run all trains to CX, and have space to reverse
Banks? Since in the off-peak the Bank/CX demand ratio falls dramatically,
this would serve people much better.

Yes but in the eventual split Morden goes with the City, so preparing people
for the idea that Charing Cross is accessible only by interchange is a good
long term strategy for making the split acceptable. One can't make a strong
opposition case to the split on the basis of these throughs being lost if
they've already been lost.

On Mon, 13 Apr 2009, Tim Roll-Pickering wrote:

Tom Anderson wrote:

What i don't get is why the off-peak pattern runs all through trains to
Bank, reversing *everything* from CX. There, the density of trains is much
lower, so the track issue is surely irrelevant - even with the awkward
layout, you could surely run all trains to CX, and have space to reverse
Banks? Since in the off-peak the Bank/CX demand ratio falls dramatically,
this would serve people much better.

Yes but in the eventual split Morden goes with the City, so preparing
people for the idea that Charing Cross is accessible only by interchange
is a good long term strategy for making the split acceptable. One can't
make a strong opposition case to the split on the basis of these
throughs being lost if they've already been lost.

Crafty!

tom

--
Information is not knowledge. -- Albert Einstein

"Tom Anderson" wrote in message
rth.li...

There's a rather nice diagram of Kennington on my site at
http://www.geocities.com/Athens/Acro.../stations.html
In particular, Charing Cross reversers don't have to share track with
any
City trains, whereas City reversers have to share track first with
Charing
Cross-Mordens and then with Morden - Charing Crosses. LUL are well
aware
that the West End is much busier than the City outside the peaks, but
for
fit people a cross-platform interchange is practically as good as a
through
train.

I can understand why thery run most trains to Bank in the peaks -
because of the track layout, plus the lesser fact that the Bank/CX
demand ratio his higher in the peaks than off-peak.

What i don't get is why the off-peak pattern runs all through trains
to Bank, reversing *everything* from CX. There, the density of trains
is much lower, so the track issue is surely irrelevant - even with the
awkward layout, you could surely run all trains to CX, and have space
to reverse Banks? Since in the off-peak the Bank/CX demand ratio falls
dramatically, this would serve people much better.

There are still 15tph on each branch off-peak. If all Banks reversed at
Kennington then there would be 30tph on the section between the junction
and the siding. Also trying to reverse a train every 4 minutes in 1
siding would be pretty difficult.

Peter Smyth

I think they did say that 24 trains per hour is possible without the
split, 30 trains per hour wouldn't be, right?


I do hope to see the split coming. The Northern Line has clearly been
more reliable the more it has been split up, and it just makes
operation so much easier and reduce the chance of delays. Just make
sure that both Kennington and Camden Town can handle it.

It would also make the choosing a branch when I go to work much easier
as I leave from Camden Town. The number of times I (and many others)
run to one platform, then run back to the other, is really quite high.

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.

At Kennington, terminating the Charing Cross services there also means
that the empty trains do not need to be checked by station staff (they
were removed some time ago), whereas Bank line terminators would still
have to be emptied as they reverse in a dead-end siding. Apparently it
is OK for passengers to be carried around the Kennington loop line if
they don't get off.

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.

On Apr 14, 4:12*pm, MIG wrote:
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.

But at the moment, there may be two services going the same way in
different platforms and allowance has to be made for this.


(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.)

You're forgetting that there are two routes potentially leading in and
it is the dove-tailing of these that decreases capacity.


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.


Some of the connections are too short to take a train, for example the
connection from the SB Edgware to SB City is too short to take a
train, until the preceeding train has made room. If the preceeding
train comes from the Barnet branch, it has to clear the section before
the pointwork can be set up for the ex-Edgware train.

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.

What you are failing to see is that keeping the point work in one
position means that the trains don't have to wait at Camden Town for
the route to be clear and set. You get more trains through the
junction because you don't have to leave space for the two services to
intermix, trains will run more reliably through the junctions because
they (should) be coming at a fixed interval from the same branch. At
the moment, there has to be some allowance for a train arriving
slightly late from one of northern branches in the timings for the
other branch. The suggested 24tph is a train every 2 1/2 mins, whilst
20tph (which is the approx. frequency at the moment) is a train every
3 mins, that extra 1/2 min will come from not having to path trains
from the two northern routes into the two central routes.

On Apr 14, 4:12*pm, MIG wrote:
There are no flat junctions to consider whichever way they go

But there are still inherent conflicts. Only one train at a time can
enter each of the northbound platforms at Camden, and only one
southbound train at a time can enter each of the Bank or Charing Cross
branches. So, for example, if an Edgware-Bank train leaves Camden on
time, and a High Barnet-CX train for whatever reason leaves 30 seconds
later, the Edgware-CX train behind the Edgware-Bank train is also
delayed by 30 seconds while it waits for the signals to clear
(assuming it was timetabled to run at the minimum signalling headway).
Then all of the trains behind are delayed. Your achieved tph drops a
notch each time this happens.

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

I think you mean signalling headway (or something like that), which
indeed it doesn't affect. But you also have to add a bit of padding to
account for any small delays or variability in each train's progress
before you can pin down an achievable tph figure. And as I've tried to
illustrate above, the junctions at Camden mean you need a lot of this
padding. This isn't about disruption, this is about simple variations
in when trains arrive, which each and every train has a little (or a
lot) of.

U

On Apr 14, 8:39*pm, wrote:
On Apr 14, 4:12*pm, MIG wrote:





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.

But at the moment, there may be two services going the same way in
different platforms and allowance has to be made for this.



(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.)

You're forgetting that there are two routes potentially leading in and
it is the dove-tailing of these that decreases capacity.



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.

Some of the connections are too short to take a train, for example the
connection from the SB Edgware to SB City is too short to take a
train, until the preceeding train has made room. If the preceeding
train comes from the Barnet branch, it has to clear the section before
the pointwork can be set up for the ex-Edgware train.

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.

What you are failing to see is that keeping the point work in one
position means that the trains don't have to wait at Camden Town for
the route to be clear and set. You get more trains through the
junction because you don't have to leave space for the two services to
intermix, trains will run more reliably through the junctions because
they (should) be coming at a fixed interval from the same branch. At
the moment, there has to be some allowance for a train arriving
slightly late from one of northern branches in the timings for the
other branch. The suggested 24tph is a train every 2 1/2 mins, whilst
20tph (which is the approx. frequency at the moment) is a train every
3 mins, that extra 1/2 min will come from not having to path trains
from the two northern routes into the two central routes.-

You may be right, but in that case what is the signalling work meant
to achieve?

My assumption (also in reply to Mr Thant) is that the potential
improved headways will not be exploited fully, and we'll get what they
could have been without the split, but with the split added to improve
reliability.

On Apr 14, 9:52*pm, MIG wrote:
On Apr 14, 8:39*pm, wrote:





On Apr 14, 4:12*pm, MIG wrote:

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.

But at the moment, there may be two services going the same way in
different platforms and allowance has to be made for this.

(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.)

You're forgetting that there are two routes potentially leading in and
it is the dove-tailing of these that decreases capacity.

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.

Some of the connections are too short to take a train, for example the
connection from the SB Edgware to SB City is too short to take a
train, until the preceeding train has made room. If the preceeding
train comes from the Barnet branch, it has to clear the section before
the pointwork can be set up for the ex-Edgware train.

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.

What you are failing to see is that keeping the point work in one
position means that the trains don't have to wait at Camden Town for
the route to be clear and set. You get more trains through the
junction because you don't have to leave space for the two services to
intermix, trains will run more reliably through the junctions because
they (should) be coming at a fixed interval from the same branch. At
the moment, there has to be some allowance for a train arriving
slightly late from one of northern branches in the timings for the
other branch. The suggested 24tph is a train every 2 1/2 mins, whilst
20tph (which is the approx. frequency at the moment) is a train every
3 mins, that extra 1/2 min will come from not having to path trains
from the two northern routes into the two central routes.-

You may be right, but in that case what is the signalling work meant
to achieve?


As the resignalling work will include ATO, it should lead to shorter
times between stations and so quicker journey times. The automatic
operation on the Central line certainly did this.

My assumption (also in reply to Mr Thant) is that the potential
improved headways will not be exploited fully, and we'll get what they
could have been without the split, but with the split added to improve
reliability.

Timetabling more trains through the junctions with the current mix of
services looks like a recipe for unreliability to me, as the leeway in
the timetable at Camden will be less.