As a former driver at both Arriva and Go North East I would say disciplinary action is fairy common even for matters which I would class as trivial and could be sorted out with a quick chat. I would also say when people get promoted (drivers to managers) that person seems to all of a sudden forget what it was like to be a driver. I will give a couple of examples from my past:

Arriva I was driving and my light was on green. Quick check to my right and I noticed this car that was flying along the road to my right so I slowed down (I was in a line of moving traffic with cars in front and behind). Surely enough this car over took the cars waiting at his red light on the wrong side of the road and came through the lights at a fairly high speed. I had to brake and swerve to avoid being wiped out. I clipped the railings to my left with the middle of my bus. There was a few scratches but I could carry on. I reported this and surely enough I had a disciplinary with a new graduate manager. She suggested I go back to the driving school for a week and that as a professional driver I should have expected the car driver to do that (the professional driver bit is used quite a lot by managers). I spoke to the depot manager at the time and he sided with me and said no further action and that the graduate was 'over the top.'

Second incident was at GNE. I was sent home by a manager for being unwell. He stopped me returning to work the next day so I returned after the weekend, my next working day. Middle of the yard, in front of everyone, he gave me a formal warning disciplinary for my attendance because he sent me home. The previous time that I was off sick was because I had an operation on my back. This had to be investigated by a manager to make sure I want lying (all my medical records and letters provided and occupational health stopped me returning as my wound had not healed fully). I was under investigation for around 1 week for this. The union, in all these instances, were very supportive.

There is definitely a them and us feeling I would say between managers and drivers. Some managers are better than others and do make the effort. Others come out in a rash if they have to leave their desks. It spoils what can be a decent job and in turn reduces morale and probably has a lot to do with staff retention and ongoing recruitment. As stated above, this is industry wide and not company specific. I loved my job but no amount of money could get me back now.