Sky Trains

Driving past a train station....

Maggie: Does that sign stand for train?
Bonnie: Yes.
Maggie: What about subways? That's a train.
Bonnie: Yes, subways are underground trains.
Maggie: Oooh! THAT'S why they're called that!
Bonnie: Yes.
Maggie: What about the trains in the sky??
Bonnie: Monorails??
Maggie: Yeah....monorails. Where are those?
Bonnie: Various places.
Maggie: RI?
Bonnie: No..... there's no monorails in RI....