The 150s nearly always meet or exceed their planned availability target. North of Caerphilly being shut doesn't help much. Just means lots of spare class 231s.
When day after day I see cancellations blamed on train failures or more trains than usual needing repairs it makes me think that the trains aren't reliable enough to run the timetabled service.
From my point of view the metric that matters isn't an availability target, it's whether it's possible to run the full timetable or not. And at the moment the answer seems to be no.
What am I missing here?
Are there too few 150s to run the full service unless the planned availability is exceeded?
Or are they being taken off to replace other types of traction that have failed?
Or are the cancellations due to something else and TfW are giving the wrong reason for them?