How often do things actually go wrong in the core though - as in, a train coming to a halt and then everything getting stuck stacking up behind it?
I know everything's sensitive to disruption elsewhere, which can cause trains to enter the core out of sequence and therefore not as efficiently as would be ideal - however I was under the impression that something breaking down in the core is now relatively rare.
More often that it should, but less often than many people think. It’s rare to have anything stopped for more than 10 minutes.
If that is so then the passenger flows on and off the train are much faster than expected, which is good, of course and does suggest that more than 24ph as a timetabled service might be possible. But can I ask some questions (don't get offended, I really want to know):
1) Is that wheels stop to wheels start?
2) Loading conditions (45s in recovery conditions implies a crush load)
3) Which station(s)?
4) AM or PM peak?
5) Mainly boarders or alighters?
1) yes
2) variable
3) all of the core stations
4) both, and off peak
5) both
You can only see this at times when the train is late, as they are normally booked 1 minute dwell. ‘Recovery conditons’ doesn’t imply crush loading though, it can be as simple as one to two trains out of sequence, requiring trains to be pumped through at 120-150sec headways to catch up. For example two trains arriving 10 minutes late right behind each other will take 8 successive 120sec headways to recover at 24 tph.
I have often seen trains through on 120second headways, but this requires sharp dispatch and sharp driving; the latter of which will be universal when ATO is in use.
The trains were specifically designed to deal with several hundred boarders and alighters in a 45sec wheels stop / Wheels start, experiments were conducted nearly a decade ago to prove it.