I am a long time Lurker but thought the original question was an interesting one, whilst I think it's difficult to compare the driving of a train to driving an alternate vehicle type, i do feel that the overriding issue isn't that train drivers are overpaid it is that much of society is underpaid in particular roles within the private sector. Teh harsh reality of taking any public service into private hands is the competitive tender process this ensures a race to the bottom for pay rates.
The railway is one of very few areas left where unions maintain strength, and this strength does ensure a fair wage. I don't believe that the average person should need to work overtime just to get by and pay bills, I do think that an average working couple should be able to buy a home, run a car, go on a holiday and maybe enjoy the weekly takeaway.
The train driver salary hasn't increased without compromise over the years, DOO far more prevalent, Sunday working now becoming incorporated and some very demanding shift work with very odd shift timings.
I work in the private sector at around £55k, to give up the "luxury" flexi working over a Monday to Friday pattern, i would want 20% more to entertain shift working as a fair trade of value.
Bus Drivers (as the comparison was originally framed) are in my opinion very much underpaid, and although the route to entry in easier for a wheel turner than a lever puller, over the years the unions have had much of the negotiation leverage removed; with a longer-term determent to those on the coal face. Pay and conditions have been slowly being eroded and people should be taking a stand