Trolly Squad

1-group of people, usually friends that hangout on the trolly system, subway, train, metro.
2-a passenger or group of people you see frequently in transit from one place to another.

The subway has different trolly squads depending on the time.
The local trolly squad are a bunch of assholes.

The school girls make their own trolly squad at the back of the cart.
The banker, cleaning lady and old man are the usual trolly squad.