It's hard to find a trade job that suits a middle-aged tall guy with a dad bod, no agility and a fear of heights.
I wouldn't be a good welder, electrician, plumber or fitter. You need to crawl and climb all over the place in jobs like that.
I looked into what they expect computer guys in the rail industry. They have formal requirements. It's not like in the IT industry where you just have to be a geek. You have to go to trade school and learn digital electronics there.
If I'm going to school, it needs to be for something new though. Maybe CNC operator or some other kind of metalwork or woodwork that you can do on a table.