Driving a HGV is nothing like driving a train and some HGV drivers now get paid as much as some train drivers. And also nursing and policing etc are nothing like driving trains but people still compare.
You will always get people making comparisons on grounds such as which job is percieved as more "demanding" or "deserving" or "skilful", along with a variety of other factors. But the reality is that supply and demand plays a huge role. Another key factor is the time taken, and resources invested, to train someone up (and whether the person has to pay for it themselves, such as pilots, or if the company pays, as in most jobs) and this also often gets ignored.
One of the jobs I do is a football coach and the salary for this can be very low:
Part-time hours: 25 per week
Salary Range : £12,500 to £13,750 per year dependant upon experience
However there will be no shortage of takers for that role, guaranteed. I'm lucky in that I can do such a role for just a few hours a week on a more reasonable rate of pay.
Having worked in a wide variety of roles, for private and public employers, I can see arguments for or against different jobs being paid differently, but at the end of the day, it's a lot more complex than the average person might think. Some of the roles I do are paid much more generously than others but at the end of the day I pick and choose what I want to do, and if not enough people choose to do a particular role at a particular salary, then if those positions need to be filled, the salary has to rise.
Working in rail is, in general, better paid than many other sectors. Of course this is not universally true of all rail-related jobs and there will always be exceptions, but as a generalisation it's surely an undeniable fact. Whether members of the general public see that as fair or not doesn't really come into it; as the saying goes, "it is what it is". But if anyone is in a job which others think is overpaid, at the end of the day people have the right to think that. But then they also have the right to try to apply for those jobs, when they become available (which, in the case of train drivers, many many people do!)
Comparing who earns what is all irrelevant, the fact remains that Train drivers under the control of the franchised Toc's haven't had a payrise in over 4 years, that is absolutely scandalous, can anyone who has commented on this thread who isn't a driver honestly tell me they they haven't had one either?
I did a job where I had no pay rise for over 4 years, but it started on a high base (hourly salary equivalent to a train driver, although not at the highest paying TOCs), so I didn't complain. At the end of the day, if the role of train driver isn't paying enough (at any operator) then that will be reflected by an inability for the company to fill positions, and that would force the company to pay more, if they can't afford to be short staffed.