In 1975 my brother caught doubleheaded GMAM Garratts on the Pietermaritzburg line. What a sight. It was right about that time, that they changed the policy of running bunker first. It was nearly impossible to get them the correct way, unless as you said it was a short run to a location where they were not able to turn. Our 1984 trip was originated at Waterval Boven specifically to catch the sporatic ballast train workings. We got lucky and found out they were running one the next morning. It went to Breyton, and return with a dead GEA Garratt going to the scrapper. This move was water bunker first. But, as with all the best laid railfan plans, we could only get a couple of shots before dark. A few months later, on-line Garratt workings in SA were history! While the Garratts were unique and fun to watch, my favorites were still the 25NC 4-8-4. "Baby Niagaras"!
I have posted a photo below(click on)of a 4-8-4 at 60 mph on the Orange Express. 60 inch drivers on 3 foot 6 inch rails. Some say that had SA been standard gauge(US standard Gauge), they may have had the largest engines in the world! Food for thought!
Cheers,
Greg Scholl