If you've been anywhere near Sky Harbor Airport either dropping off or picking someone up, you've probably noticed that the Sky Train is up and running.
While it isn't carrying any passengers yet, these practice runs are a major safety step before the big launch.
The train will make stops at the 44th Street light rail stop, the east economy parking lot and Terminal 4.
There's no word on when the train will officially begin taking passengers, but Sky Harbor Airport officials say it will happen sometime between January and March.
Video: FOX 10's Kristy Siefkin reports.