Thanks everybody!
As for Garratts, I do not know really. The steam trains that I remember were moved by Henschel and Beyer Peacock locomotives.
Here you may find better info:
http://lfu1.tripod.com/AUAR.html
http://lfu1.tripod.com/index-6.html
I'll try to find better sources for you.
Have a great day.
Raider