RE: Centennial locos
As far as I know, nobody makes a model of this locomotive. A 1:29 or 1:32 model of this locomotive would be HUGE, and would require very large radius curves to accomodate it. I don't have an illustration handy, but I believe the trucks had at least four axles each. This means that the trucks alone would require larger than normal curves, but the locomotive, itself, would probably be over a yard long in 1:29 or 1:32 scale. These were impressive locomotives when they were built in 1969. They were only used on the Union Pacific, and had to stay with divisions on that railroad which had sufficient large radius curves, so the curve problem was "prototypical."
Hope this helps,