CREATE TABLE table_79439 ("Class" TEXT, "Railway number ( s ) " TEXT, "Quantity rebuilt" FLOAT, "Rebuildjahr ( e ) " TEXT, "Type" TEXT)

What was the Rebuildjahr(e) for the T2AA class?
SELECT "Rebuildjahr(e)" FROM table_79439 WHERE "Class" = 't2aa'
SELECT "Rebuildjahr(e)" FROM "table_79439" WHERE "Class" = 't2aa'