If I recall, there were some issues with Athearn SD locomotives derailing. Different sized wheels could be behind those issues.
Marlon
See pictures of the Clinton-Golden Valley RR
RR_MelI’ve been remotoring several Athearn SD frames and I came across a slight surprise. I thought Athearn SD frames all had the same size wheels. Out of one SD9 and four SD40-2s there were three different wheel diameters. These varied from .475”, .478” and .482”.
That's a bit of a let down. You would think that consistent wheel size would be a priority but apparently not.
I don't have any Athearn locomotives, but perhaps it would be wise to include a check of the wheel diameter on any locomotive that doesn't like to stay on the tracks.
Dave
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!
Mel so now I have to go check all my athearn engines thanks lol
just wondering some of those could be from gp style engines same wheels ??