Free tram sectors in inner Adelaide and Melbourne

Does anybody know when the free vintage tram loop and the free tram zone, respectively, in Melbourne and the free sector of the Adelaide tram were introoduced and by which government in each case? (I can work out the government if necessary if a get a date for each.)

As a non-kosher rider to the Adelaide question, does anybody know when the two free Adelaide bus loop services were introduced? TIA.

Tony P