Excessively complex timetables and disruption issues

[Bletchleyite]

Everyone is I'm sure well aware of how excessively complex some timetables are, and how this means that one delay then knocks onto a very wide area. The classic was the cross-Birmingham West Midlands Trains operation in 2019, which totally fell to bits on a daily basis and was replaced with a timetable with far less interworking which is somewhat more stable (though not perfect).

I believe the likes of Northern do a lot of crew and unit interworking (e.g. the "Lancashire triangle", but not only that), which must surely contribute to the severe unpunctuality and unreliability of the present network. I do also note from a thread a while back that Avanti drivers have an agreement not to do the same destination twice in one day, though that really only applies to Birmingham as other routes are too long to do it anyway.

So the question is - is it viable to simplify unit and crew diagrams on something like Northern, so a given driver and guard team and unit would stay on one route (or a maximum of two) for the full shift? The big advantage of this would be that like Merseyrail where things mostly do stay on route if something ends up late you can just bring it back on time by cancelling a round trip and dropping it back in on time rather than having to either do fast-running or leaving things out of sync?

What considerations exist that might prevent this? Obviously we need to fit PNBs in, but if you consider that (I guess) the 7am-11pm Ormskirk-Preston service is basically three shifts can this be worked around, either by some longer gaps or by overlapping them in some way in preference to interworking? And would that mean that if something went wrong (as it always will) the knock-on is only to that line? We obsess about not holding connections due to knock-on, yet interworking of crews and units effectively does the same.

 

[6Gman]

It's a balance.

At one extreme you can screw the diagrams super-tight to maximise productivity and reduce cost, at the other extreme you build in huge margins but at extra cost.

There is a sweet spot somewhere inbetween that strikes an appropriate balance.

But ask six diagrammers and three managers where that sweet spot lies and you'll get nine answers!

Personally (as a now long-retired diagrammer) the current balance is too centred on economy rather than robustness.

 

[Bletchleyite]

Personally (as a now long-retired diagrammer) the current balance is too centred on economy rather than robustness.

That's how it feels to me too. If we consider Northern (which is a good example) if things were more self-contained a driver or guard going sick might mean, for instance, that you have to find a bus replacement for that one line as you can't run the rest of that shift's service - but as things are now it'll knock on all over the place. Or if it was self-contained and a passenger was taken ill causing an hour's delay you might have to bin off a round trip, but as things are now it'll probably wreck Castlefield and thus most of the North.