You will be asked several questions and IIRC they are along these lines. I sat the same interview last year.....
When have you dealt with a particularly rude of difficult customer?
When have you gone that extra mile to help a customer?
When have you had a difficult conversation with a work colleague?
When have you worked as part of an effective team?
Around the station, which passengers may need help?
Have you any experience of handling money?
When have you had to help several customers at the same time?
and the usual questions about why you want the job, what you know about the company and your work experience.
What station is this for?