I have to agree with other posters about getting your PPL first, it's great fun as a hobby, but as a career, you're not in control. Horrible shift patterns, you fit in with them. Stick to passenger train driving, your shifts will rarely start/finish before or after midnight decent salary allowing you to be able to afford a good lifestyle. Just don't transfer to freight train driving, I know this from experience, £120k+, shift patterns all over the place, no life, burnt out at 56. Add life to your days, not just days to your life.
You're only here once, enjoy it.