This data is created and maintained by MARTA, not the City of Atlanta. The most up-to-date GTFS data can always be found at https://www.itsmarta.com/app-developer-resources.aspx This layer contains in
The Hamburger Verkehrsverbund (hvv) provides the timetable data of the network area monthly in GTFS format. The data includes information on lines, stops, departure times, etc.