Chuck,
Kato made engines for Atlas back in the late 80's and into the 90's. I believe they made the RS-3, GP-7/GP-9, RS-11 and SD-9's that Atlas released during this time. They may have done some others as well.
The loud noise is probably a lack of lubrication issue that can be fixed with some Labelle 107 or 108 oil applied to the bearing blocks and some Labelle 106 grease applied to the worm gears. Apply sparingly.
If you search this site for Kato locomotive lubrication you'll find some information in some older posts.
Scott