S Class locos where introduced into Victoria in the 1950s, after the success of the B Class locos. There are a couple still in service today but only just.
S303 was one of two S Class locos painted in Freight Australia green. (301 was the other.)
This model was a Bachman F5 (I think) in Sante Fe livery - my first N scale loco, not a Victorian S Class. It was part of a cheap set and has running qualities to match the price. I decided I didn't want Sante Fe any more so this became my experimental air brushing specimen, and if you use some imagination and perhaps a poor pair of glasses, you can pretend it is an S Class.