If you are a train driver you will know there are many many applicants for each vacancy reflecting the high rate of pay and good working conditions. Yes, I am and there are many applicants; a high percentage of whom do not get through the first stage.
The qualifications needed for the job are not particularly difficult. Agreed, but a lot still fail.
A few O levels at basic pass grades and compared with other jobs on that level of money, a very short period of training, most of it on the job. Most applicants with O levels are now a bit too old to apply, but I get your point. Training is at least three months of classroom then a minimum 225 hours in cab practical handling, if they passed their classroom/theory tests.
You only need to sit behind the cab of a Blackpool tram to see how easy the job is to master. I have never driven a Blackpool tram but an professional driver can make a job look easy. I drive Mainline Trains at speeds up to125 mph. And I make it look easy too.
If we can automate car driving, trains will not be far behind. I don't see many driver-less cars driving about.
Then any numpty can sit in a cab and press an override button for about a 1/4 of the money should things go wrong. If you are happy with poorly-paid numpties being responsible for when the automated systems fail, god help you.