The 2'6"gauge lines operated by the Victorian Railways required more powerful locomotives.  Given that there were many tight curves and steep gradess, 2 Garratt articulated locomotives were purchased.  Numbered G41 and G42, they were allocated to to the Walhalla and Crowes lines respectively.
This DVD contains a brief history of G42 on the Colac to Crowes line,and its eventual restoration for use on the Puffing Billy Railway.