Thanks for the quick reply. I understand, family and job first, the hobby comes second.
Probably Fusion360 cannot handle repetitive surface details, I have never tested.
I will re-design twice the body (one version with smooth surface for the ex-JZ-441 and another with embossed/engraved surface for the SJ Rc-6) by using OpenSCAD, very easy. Thanks again for sharing your nice locomotive with the community.