Alan --
Looks like very few people are willing to step up to the plate with specific suggestions for individual locomotives.
A few that I'd recommend are:
81997:599, NSW 59-class
81997:450, SAR Garratt
126323:453, SAR T-class
81997:727, VR R-class
81997:302, VR S-class
101839:1033, BR 9F
2512:2371, BR Class 37
193148:1329, BR 4MT
95761:1001, Clinch SD40
152373:9000, FR8Net Dash9
315087:1074, The General
193148:1399, MR Hudson
46075:6930, UP 0-6-0
40334:90020, UP C36-7
113556:51055, UP Dash8
113556:1000017 UP GP60
I just hope that I don't offend anybody with a list like this. There are literally scores of excellent and deserving locomotives on the Download Station, it's just that I find those listed above very useful for my particular operations.
Regards,
Phil