"tim" wrote in message
...

"David Fairthorne" wrote in message
om...
Trains should run at the same minutes past each hour in the regular
off-peak periods. But should the same "clockface" timetable continue
throughout the peak periods? The Strategic Rail Authority seems to
like the idea, but in my opinion they are misguided.

My main reason is that whenever peak-hour extra trains are added to
the regular trains, in order to provide needed extra capacity,
passenger loads will (as a general rule) be unevenly distributed
between trains.

This is what they do on many S-bahn networks.
The lines cycle within a 20 minute period [1] and all paths are
used in the peaks. Historically, in the off-peak they missed
out every other train for a (annoying) 40 minute frequency.
However, as off peak loadings have increased many lines
require two trains per hour and in order to avoid re-pathing
all the trains they run 2 out of 3 in the normal paths with 20
and 40 minute gaps.

From a customer pov it sucks, from an operation pov it's
much better.

tim

[1] Yes I know, there are some networks that cycle on
a 30 minute frequency.


Thanks, Tim. That's interesting.

So the S-bahn has equal intervals in peak hours but unequal intervals
(equally spaced paths some of which are unused) in the off-peak. That would
work okay, but it could deter some off-peak passengers and they are the ones
you want to attract.

The reason why I was asking was the controversy about the SRA proposed
service plan for the Integrated Kent Franchise (currently run by the South
Eastern). What the SRA wants is (I presume equally spaced) clockface
timetables running throughout the day, with additional trains interposed
during the peak periods. I am against that because the additional peak hour
trains would (in general) upset the equal intervals, resulting in unbalanced
loads. That is, unless the peak service is exactly double the off-peak, and
that seems too restrictive.