Ticket barrier

A ticket barrier is a machine that you have to go through when you go on a train or metro. It has arms that go up and down, and you need a ticket to get through. When you first go to the station, you go to a machine that gives you a ticket. It's like a little piece of paper that says you paid to go on the train. Then, when you get to the ticket barrier, you put your ticket in a slot and the machine reads it to make sure it's real. If it is, the arms will lift up and you can walk through to the train platform. If your ticket is not real or you didn't pay for it, the arms will not lift up and you won't be able to get through. So, always make sure you have a proper ticket!