When you join the group for Stepford County Railway, you are automatically given the Trainee Driver rank. The rank does not provide any extra amenities in-game, However, it does mean you can rank up to positions such as the Qualified Driver rank if you have 60 experience.
There are over 22K+ members as this rank due to it being the starter rank and some people don't try to rank up after joining the group.
Trainee Drivers can still try out Dispatcher and Signaler roles by playing on a VIP server.
The Trainee Driver rank is the in group equivalent to the Guest rank.