To all,
I found the Reversing Gear Control F/N/R on my Santa Fe diesel. It is a thin lever that protrudes from the bottom of the engine between the two wheel "trucks".
When configured as A-B-A and three passenger cars, it moves very very slowly in reverse. I have a 90 Watt Transformer on a small layout.
Now I need to resolve the horn battery!
Again, thanks for the help!
aaganz