According to my copy of the "Greek railways" book, the American-built steam locomotives that circulated in Greece were classified as:
(class with Greek letters, axles, builders, construction year, weight and horsepower).
Class G401-420, 1' D 1' h2, ALCo, built 1915, 84.4 tons, 1100 hp. Later got reclassified as Ia701-720
Class Da51-70, C 2nt, Davenport, Vulcan, Porter (ex-USATC tank locos), built 1943-1944, 46 tons, 730 hp.
Class Thg (Theta-gamma) 521-537, 1' D h2, Baldwin, ALCo, Lima (ex-USATC S-160), built 1942-1944, 73 tons, 1200 hp
Class Thg 551-560, 1' D h2, ALCo, built 1944, (ex-USATC S-160, oil burners), built 1944
Class Thg 571-595, 1' D h2, Baldwin, ALCo, Lima (ex-USATC S-160, oil burners, ex-FS class 736). built 1942-1945
Class Lg 991-998, 1' E h2, Baldwin, built 1947, 90 tons, 1700 hp (oil burner)
Metre gauge: Class D101-D108, 1' D 1' h2, Vulcan, built 1947, 55.4 tons, 875 hp (ex-USATC S-118, later reclassified as Da7101-7108)
I didn't add in the list the really obscure steam locomotives in industrial/tram/military systems, neither diesel locomotives
Regards from Athens, Nick Fotis