To answer your railway question, no, depending on what you do, there won't be any hard graft unless you go in as a labourer. There are different routes you can take, Lookout, Coss, Engineering Supervisor, Crane Controller, Strapping out, etc etc.
I don't know how much being a HGV driver pays but in a different life time when I was doing some railway related stuff, I was paid anywhere from 15-35 bucks an hour. This was about 10-12 years ago now. I never remember leaving the site access office much.
What's also 'beneficial' about the railways for someone in your situation, is that there's a big emphasis on weekend work. That's when all the heavy engineering gets done as the lines aren't as busy. Same for Christmas day. Back in the day, I done a few Christmas Eve shifts and got paid quite a few 1000 for just turning up. As I wasn't an idiot with money, just that shift alone paid my rent for nearly 6 months. Companies will also be happy if you just want to work weekends as that's when they find it hard to get people to work.
Look it's just a suggestion. I've no clue what it's like nowadays but I can't imagine it to be much different. It's terrible hours, rubbish work (whatever you end up doing) but it'll hopefully teach you a thing or two about enduring hardship and not slacking at university (otherwise the railway might threaten to become your career!) There's nothing like having to do 9 miles worth of bridge inspections in pouring rain at 2am on a Sunday morning. Nothing.
Have a little look around, ring a few companies and see what's on offer. Don't sound like you have much going on at the moment anyway.