The older Proto 2000 FA engines had moving fans using a belt off the flywheel/pulley. I don't know how big they are but they have a see-through grille so you can see the fan moving. Don't know if this is adaptable to the Athearn units? Worth a look though.
-Bob
Life is what happens while you are making other plans!
I've been thinking of adding a smoke unit to an athearn sd60 and matching it to the manual notching. At the same time to add realism to the athearn dynamic brake fan and cool the engine I thought about taking an spare motor (it's really small) and making a working dynamic brake fan. I will need a separate fan blade and a new covering for it. Does anyone know where i can find a 6 bladed fan about .65" in diameter? I will also need a new cover but I saw plenty on walthers. I think i can easily connect the motor to the fan blade, I just can't find any.
Here's a link to what I'm trying to recreate as far as smoke: http://www.youtube.com/watch?v=ymjVxEaR3MQ. The sd60's are in the back but they are all smoking and the smoke is white so that's good...