If it is for Southern than you will be put in a "scenario". You will take on the role of a conductor onboard a fictitious train company. Before you go in you will be given about 10 minutes to read through a brief which will tell you what you can and cant do and what is available to you (ie phone)
You will be able to take notes during this time.
You will then go into the role play where another person will take on the role of a passenger, and essentially you listen to what they say and go from there.
NB I wont go into too much detail as it would be unfair on other candidates, if you are good enough for the role then you will know what to do!
The interview will be pretty standard: Why do you want to work for the company? What do you know about them? Where do they go? What sort of trains do we run? What skills to do you have that would be good in this role? Have you worked as part of a team? Have you worked on your own?
There will also be operational questions: When have you dealt with an emergency? What happened? What did you do? What happened then? What was the end result? How did this make you feel? etc etc
Name a time when you have worked to set of rules? What, when, why etc...
Do you think rules are important? Why etc...
Have you ever taken part in a training course lasting several weeks?
What is your best skill? What is your worst?
All along those lines...
Sorry for poor grammar its been a long day and I am writing as quickly as I can before I go to work? Hope this helps.
Francis (conductor!)