Just doing a little bit of digging into some of the services that run/didnt run on my local line, the Maryhill line particularly round the peak today around 4 til 6 o clock say, i have checked RTT i the train i travelled on is not shown, which was the 1706 from Anniesland due to arrive Glasgow Queen St at 1728 also as you will see from this it says cancelled:
http://timetablehistory.com/times.aspx?uid=Y60671&date=20220518
Now that might not be too unusual, though also looking at the stock for the return at 1735 from Glasgow back to Anniesland, it says it was run by 158710 where as the train i was on was a 170, again which would have been the return trip, Now granted i know that it could have easily been a set swap at that time.
the other thing though that is interesting is that the 1628 from Anniesland ran arrived at Glasgow Queen St at 1654 and i assume was supposed to do the 1704 back to Anniesland but alas this is one of the services that DID get cancelled, now granted it could have been that the driver had he taken that train back to Anniesland could have gone over his working hours etc, but that set sat in Queen St for over an hour before departing back out at 1803 again on an Anniesland turn, so it could very well have run and still got back for 1803 to do this next turn but as i say was it really just a case of the driver bringing the train in at 1654 couldnt do the next turn as he would have gone over his hours, hence the missing 1704 GLQ to ANL and 1732 ANL to GLQ return.
GLQ=Glasgow Queen St
ANL=Anniesland