Why is “more trains than usual needing repairs” seen by some as an “excuse”? It’s a perfectly good reason!
Yesterday, I had to send out a 4 vice 8 Class 387 formation as one 387 didn’t make it off it’s B Exam in time for morning service, instead of the 4 units we can have on maintenance we ended up with 5 leaving us one short for traffic, so that “excuse” is actually spot on.
As usual the armchair experts with their ‘tin-foil’ conspiracy hats on, obviously know better!
I think it’s the ‘than usual’ bit. A couple of summers ago GWR had a large number of services affected due to this reason over a relatively long period of time. So it was actually usual to have short formed trains.
Something like ‘A shortage of trains because of maintenance requirements’ may be more apt in prolonged periods of stock shortages. I’m aware that this reason doesn’t exist and TOCs have to use the closest fitting reason.