I’ve been thinking about “rebuilding” my locomotives so to speak. I currently own 2 Athearn RTR Ac4400s (NS/Kcs). The KCS runs like a horse, but the horse, well doesn’t run that well on the NS. I also have a Genesis SD60 that runs well. I’ve been thinking about ways to make the locomotives run better. Ya know, more pulling power, better starting stopping, smoother running. I’ve read a few places on here about people replacing the motors, and running gear. I’d like to get into it, but I’m not really sure where to start. I feel like it’d be an interesting subject to learn, and useful for the life of the hobby. I’m happy with how my KCS 4400 runs, but the I’m thinking the NS one needs a trip to the shops. Any tips?
My first inclination is to advise you to “lube and tune” the locos before you attempt to replace motors or gears or the like. Over the years I’ve learned that it doesn’t take much dirt or dryness at critical points to mess up a locos operation.
So, I would take the loco apart (make notes or take a picture during the process to aid in getting it back together), and first clean off any gunk, and oil up the motor at the various contact points of the shaft/armature. Then I would work on the gears, making sure there are no burrs or rough spots and lube them as needed. Remember, “more is not better” when it comes to oiling a loco. Lastly, I would make sure the wheels and electrical contacts are clean and smooth.
That being done, your loco should run as good as it can. Of course if it has not been run much, it still needs breaking in - run in both directions at different speeds (usually pretty much done in a couple hours or so).
Of course maybe your track/wiring are not as clean and solid as they should be. So before you put those clean loco wheels on the track, make sure its clean. And if you are running DC, you should have feeders every 6 feet or so, and if running DCC, then I would have them every 3-4 feet.
If all that is done properly and the loco still does not run as you wish, if the loco is a regular Athearn (not Genesis) it is probably not worth replacing the motor or gearing. If it is a Genesis, then something is definitely wrong if it still runs poorly.
I’m into HO now, but when I was in N scale, I ran some of my locos so much that I wore off the nickel plating off of the wheel treads. So I would also check the wheels to make sure they are bright, shinny, and smooth. Also, check the axle gears. Some of them can split and cause problems. If you have a split axle gear, it thumps when the loco is running, and of course speeds up and slows down when the loco does.