SkyTrain is one of three train options at Hartsfield-Jackson International Airport in addition to MARTA and the plane train. The service connects passengers to a rental car hub, two hotels and the Georgia International Convention Center. And one of the best features? It’s free to ride.

Located at the end of baggage claim and just outside the doors marked “Ground Transportation,” the SkyTrain is a great transit option whether or not you are flying in or out of the airport. Here three useful things to know:

The elevated train travels in a loop 24 hours a day, and quite frequently. Trains arrive every three minutes during peak daytime hours and no more than every 10 minutes at night.

There are only three stations: Airport, Gateway Center and the Rental Car Center. It only takes five minutes to get to the Rental Car Center if you need to pick up a car at the airport.

The easiest hotels to get to near the airport are next to the Gateway Center stop: Marriott Atlanta Gateway and Springhill Suites Atlanta Gateway. Hands down, if your late-night flight gets cancelled or you otherwise get stuck at the airport, these two hotels are extremely easy to get to at all hours of the night.