Jim,
it was all about train length and tonnage on our old hook/buffer drawbars, in the North Island we had 45 U-28C Dx or 145 Da, 17 Db so 3000hp or two Da's or 3 Db's were about all that was needed until the 80's, were used regularly. Then along came the 4000hp electrics running 2 and 3 of them. Nowadays 4 and 5 diesels are common. Search youtube for the coaltrains over Arthurs Pass for the 5unit Bankers.
Crossing between units wasn't hard without rear platforms, you had to remember not to hit your head on the the protruding headlight/number board housing. The Df, a six motor version of the Da had a narrow rear platform much like an SD9 but all the US built loco's due to lower ng frames, there were no step wells to hop across. No full length handrails either
That ugly yellow/grey and orange paint scheme came about in '78, I preferred the old speed whiskered carnation red. I often wonder if the old General Palmer had gone to New Zealand instead of England for his inspiration and chosen colonial gauge then what would have the Da/Db looked like in Rio Grande paint?
Actually it was all about the rain and the atmosphere of the shot, not your "normal" fluffy white clouds and blue sky picture.
Chris
in New Zealand