On 24 Jan 2007 07:25:08 -0800, "Neil Williams"
wrote:

On Jan 23, 10:36 pm, "Richard J." wrote:

... the timetable in ruins! It always amazes me that there seems, on
the manually driven lines at any rate, to be little or no automated
assistance to the driver to keep to the timetable.

Is it really necessary to stick strictly to the timetable if you're
running a service as frequent as every 2 minutes? Surely you'd just
feed the trains "into" the system at roughly the right frequency from
each end, and keep them moving as quickly as possible. I'd agree,
though, that if the service is really that frequent holding connections
is probably counter-productive.

Yes it is necessary to run to timetable. As Steve F has explained there
are train crew rostering issues as well as getting trains through
specific junctions in their correct "slot". If we look at the JNP lines
the Northern is most susceptible to very small delays building up and
then becoming minor delays and then potentially severe delays (to use
the standard terminology). This can happen even where there are no train
or signal failures - just little incidents like dwell times taking
longer than planned, a very short passenger incident or a slightly
delayed crew switchover. The line has several complex areas which need
to run like clockwork to ensure a really good service - Finchley
Central, Golders Green, Camden Town, Kennington and Morden.

The Picc Line is generally fine unless things go wrong at Arnos Grove or
Acton Town and then you have the equivalent of a heart attack to the
service. Acton is the worst place as it's very complex, you have the
impact of the District Line service and too depots close by - Ealing
Common and Northfields. You also have crew changes at Acton as well. It
can take the Picc a long time to recover from incidents as the service
is so intensive and busy and there is not very much flexibility on the
core section from Acton to Arnos Grove to allow trains to be turned,
reversed or parked out of the way.

The Jubilee Line has much more by way of sidings, crossovers and bay
platforms and this allows easier access if technicians have to get on
the track to fix things and recovery is generally faster than on the
other JNP lines.

Your "feeding in" comment is perfectly applicable to completely
automatic systems like VAL, Meteor and the Singapore North East line as
there are no staff that have to be rostered to each train. The computer
controlling the line will balance out the service to pre-programmed
parameters or else the controller can intervene and run trains where he
wants them in response to demand. This does require a good initial
system design with turning points and sidings to allow trains to be
shuttled to the busiest points and then placed into service.

--
Paul C


Admits to working for London Underground!

This is getting close to a subject that I am interested in.... how come
it's not possible to balance the number of trains going to
ealing/richmond/wimbledon?

I use the richmond branch, and it is quite common to have 3-4 ealing
broadway trains go past before we get a richmond train.

Would it not be possible to even out the service at earls court? You
could have two trains at the platform, say one is to ealing, one to
richmond, let everyone swap over, and then release the trains. That way
nobody gets to miss a train to their destination and a better service
frequency is maintained.

-- Harry

On Jan 25, 9:38 pm, Paul Corfield wrote:
On 24 Jan 2007 07:25:08 -0800, "Neil Williams"
wrote:

On Jan 23, 10:36 pm, "Richard J." wrote:

... the timetable in ruins! It always amazes me that there seems, on
the manually driven lines at any rate, to be little or no automated
assistance to the driver to keep to the timetable.

Is it really necessary to stick strictly to the timetable if you're
running a service as frequent as every 2 minutes? Surely you'd just
feed the trains "into" the system at roughly the right frequency from
each end, and keep them moving as quickly as possible. I'd agree,
though, that if the service is really that frequent holding connections
is probably counter-productive.Yes it is necessary to run to timetable. As Steve F has explained there
are train crew rostering issues as well as getting trains through
specific junctions in their correct "slot". If we look at the JNP lines
the Northern is most susceptible to very small delays building up and
then becoming minor delays and then potentially severe delays (to use
the standard terminology). This can happen even where there are no train
or signal failures - just little incidents like dwell times taking
longer than planned, a very short passenger incident or a slightly
delayed crew switchover. The line has several complex areas which need
to run like clockwork to ensure a really good service - Finchley
Central, Golders Green, Camden Town, Kennington and Morden.

The Picc Line is generally fine unless things go wrong at Arnos Grove or
Acton Town and then you have the equivalent of a heart attack to the
service. Acton is the worst place as it's very complex, you have the
impact of the District Line service and too depots close by - Ealing
Common and Northfields. You also have crew changes at Acton as well. It
can take the Picc a long time to recover from incidents as the service
is so intensive and busy and there is not very much flexibility on the
core section from Acton to Arnos Grove to allow trains to be turned,
reversed or parked out of the way.

The Jubilee Line has much more by way of sidings, crossovers and bay
platforms and this allows easier access if technicians have to get on
the track to fix things and recovery is generally faster than on the
other JNP lines.

Your "feeding in" comment is perfectly applicable to completely
automatic systems like VAL, Meteor and the Singapore North East line as
there are no staff that have to be rostered to each train. The computer
controlling the line will balance out the service to pre-programmed
parameters or else the controller can intervene and run trains where he
wants them in response to demand. This does require a good initial
system design with turning points and sidings to allow trains to be
shuttled to the busiest points and then placed into service.

--
Paul C

Admits to working for London Underground!

In message . com,
NewsPosting writes
This is getting close to a subject that I am interested in.... how come
it's not possible to balance the number of trains going to
ealing/richmond/wimbledon?

I use the richmond branch, and it is quite common to have 3-4 ealing
broadway trains go past before we get a richmond train.

Would it not be possible to even out the service at earls court? You
could have two trains at the platform, say one is to ealing, one to
richmond, let everyone swap over, and then release the trains. That way
nobody gets to miss a train to their destination and a better service
frequency is maintained.

The timetable sets the number of trains to each branch and the train
crews are then diagrammed accordingly. When the job is 'up the wall'
(an LU technical term) you don't suddenly magic up an extra two dozen
drivers to ensure balance, so the controller (who deals with the
service) and the train crew Duty Managers (DMTs, who deal with the train
crew provision) have to do the best they can with the resources
available. Much of this is working on the hoof to get the best benefit
out of the available recourse - if you don't have a driver, you don't
have a train!

Travelling times down each branch are different, so a driver who could
do a Wimbledon probably wouldn't have time to do an Ealing. Then there
are things like finishing times, meal breaks, legal parameters to
contend with, so all in all it's all a bit of a black art.
--
Steve Fitzgerald has now left the building.
You will find him in London's Docklands, E16, UK
(please use the reply to address for email)

In message . com,
NewsPosting writes

Would it not be possible to even out the service at earls court? You
could have two trains at the platform, say one is to ealing, one to
richmond, let everyone swap over, and then release the trains.

What about the Wimbledon service ... and the Olympia service? There are
only two west-bound platforms at Earls Court, so you would risk
disrupting the other branches.

Also, the Richmond and Ealing services use the same track for several
miles beyond Earls Court ... so they couldn't be released together.
--
Paul Terry

"NewsPosting" wrote in message
ups.com...

Would it not be possible to even out the service at earls court? You
could have two trains at the platform, say one is to ealing, one to
richmond, let everyone swap over, and then release the trains. That way
nobody gets to miss a train to their destination and a better service
frequency is maintained.

Don't be daft - that would be *far* too convenient for passengers! ;-)

Ian

On 26 Jan 2007 04:59:10 -0800, NewsPosting wrote:

This is getting close to a subject that I am interested in.... how come
it's not possible to balance the number of trains going to
ealing/richmond/wimbledon?

I use the richmond branch, and it is quite common to have 3-4 ealing
broadway trains go past before we get a richmond train.

If this was just after the peaks (or in the late evening), it's
probably because trains going out of service were heading back to the
depot at Ealing Common.