As above, check what companies are in your area and sign up for job alert emails on their websites.
Each company will have a maximum distance that you can live from their depot, usually about 45-60 minutes, so probably Chester, Manchester and Liverpool for you. It also depends whether you want to work on passenger or freight trains, both are very different.
You will need to research the roles and be familiar with the interview process as when jobs are advertised there are thousands of applicants, I think the last lot at my TOC had about 7,000 apply. Don't let that put you off though as it's a great job with massive rewards if you are successful.