Overtime is supposed to be just that, over time. Not expected hours just to make the system work. They should be training s shitload more drivers.
Like you mentioned earlier, my own Dad relied a lot of overtime so that we could put food on the table etc. He worked some evenings/nights and every Saturday morning that I can remember, but thankfully managed to turn up to my sport on Saturday arvos even if he rocked up straight from the factory floor in his workclothes smelling like high heaven (thanks Dad). So I definitely get where you are coming from re wanting to do O/T. If there is overtime available and some workers want/need it then great, but a system where overtime becomes expected is not how it should be.
[Disclaimer: I don't know how much forced overtime is going on at CityRail or whatever it is called these days, but if an overtime ban causes as much chaos as it has, then the system is relying way to much on it]