In message . com, Neil
Williams writes

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.

Basically yes it is. As the trains are diagrammed to run at certain
times, so are the drivers scheduled to be in certain places at certain
times to drive these trains. Where branches are involved, you also have
the issue of the trains not arriving at the junctions at the wrong times
- causing that old chestnut, 'blocking back', thus delaying the service
further. It can take over 2 minutes to get a train through a junction
and ready to accept the next train. Once a driver ends up being more
than 5 minutes late off their first half, by the time they've had their
statutory half hour meal break (which they are not paid for and
therefore is their 'own' time), they are then potentially late for the
second half of the duty which then causes more delays... and so it goes
on.
--
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)