Sign up for email alerts in every TOC that operates out of London. Also many operators require that you live within 45-60 mins commute. When you do applications ensure you get across how your experience in previous roles match up closely to a train drivers role. Eg concentration, safety, customer service. It’s ridiculous how hard it is to get straight into a train driver role. You need a huge amount of luck and the experience to go with it. If there are 10 trainee jobs going with an operator you can guarantee there will be 10,000 applicants to sift through. Just apply to everything that comes up!