I've been driving a couple of times lately .And there was only one cash register, there were a lot of people.You may not have time to buy a ticket to the train.Not everyone knows how to use self-service vending machines.And in the train, the ticket is more expensive.
There are always polite and competent cashier staff, (I use the cashier every day), you can ask questions - they will not refuse! They will advise you. Good luck and further success.