On Tue, 23 Jan 2007 21:36:58 GMT, "Richard J."
wrote:

Paul Corfield wrote:

You make the comment about timetables - I'm afraid this is a
relevant point here. The Central Line timetable is very finely
balanced - especially in the peaks so it's hard to justify extended
dwell times when you're running on 2 min headways.

I'd put it more strongly than that. If you have a peak service with 2
min (or less) headways, you MUST NOT have extended dwell times out of a
misplaced sense of courtesy. A longer dwell time at one station means
larger crowds at the next few stations which leads to enforced longer
dwell times which leads to larger crowds further on which leads to ...

... 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. The best way to deal
with crowded stations is to have a very regular frequency of trains, yet
apart from crude regulation at places like Hyde Park Corner, little is
actually done, as far as I can see, to ensure this. Indeed, scheduling
crew changes at places such as Earl's Court (District) without any
apparent monitoring of the process on the platform is sheer negligence
in my view, as it inevitably leads to erratic intervals.

I would agree with your comments about longer dwell times but they are
an irrelevance to the vast majority of passengers. They just want the
most convenient journey possible - which is what the OP is clearly
driving at. While I fully understand why the travelling public are not
concerned with the minutiae that makes the Underground work it does not
take very much at all to tip things over. I don't know how we can
effectively educate our passengers so that they don't do the things that
can cause the "tip over" effect. The counterbalance is to make sure the
assets all work properly.

As you say the most important thing is to keep pushing trains down the
line at frequent intervals with as few perturbations to the service as
possible. The simple fact is that most lines have very old signalling
and control systems that are a very long away from the best modern
systems. There are additional aids and information sources that have
been "added on" to help with train dispatch and changeovers but it's not
state of the art nor is it fully integrated to allow line controllers /
duty managers to effect the most sensible solutions very quickly. I
don't know if there is something at Earls Court to assist with District
Line changeovers.

Nonetheless there is a huge wealth of experience and knowledge that
allows service recovery to happen faster these days than it used to do
(in most cases). Some lines have much more trouble with recovery -
Northern and Piccadilly being two that spring to mind all too readily. I
only hope that the new systems being installed as part of the line
upgrades deliver the right combination of high reliability, extra
capacity and the "tool kit" for controllers to restore the train system
quickly and efficiently if things go wrong.
--
Paul C


Admits to working for London Underground!