Help! N scale Kato diesel won't run!

Model Railroader General Discussion (Model Railroader)
1

Do you know what’s wrong? I am a beginner to maintenance. My Kato EMD GP50 will run about a minute or two, and then slow to a stop and not roll, even though the motor is spinning rapidly. The motor runs, and the lights are on, but it won’t move. What’s up? It’s my favorite engine!

2

I have no experience with Kato N scale locomotives, but had that problem with an HO scale NW-2 switcher when a drive shaft twisted off.

Contact Kato USA and ask about warranty repair by them. Their mailing address, e-mail, web site, etc. are indicated in their advertisements in Model Railroader, usually on the inside back cover.

3

Thanks, cacole. This engine is several years old, so beyond warranty, and the odd thing is that it’ll run for a minute or two when it’s cold, but then quickly slows to a revved up stall mode after that. I’m stumped. But thanks for answering.

4

Do you really hear the motor “run” or is it humming,trying to run.I suggest that you run your loco without its shell to check.If the motor does run free,you’ll be able to know where its power gets lost,either driveshaft or gears.However,if the engine does “humm” and doesn’t rotate,you probably have a case of either worn brushes or motor armature that shorts out after heating up.In this case you will likely have a pretty hot motor that would call for replacement.

5

Thanks, Jacktal. It sounds loud enough to be rotating and not just humming, but I’ll try it without the shell, and check for contacts. I don’t even know what brushes or commutators or any ot that stuff looks like, so this should be interesting! I suspect a drive shaft out of place somehow, because the motor is loud at full throttle.

6

More likely than not it is drive shaft/gear related. The brushes are inside the motor so you won’t see them. But if the motor is turning smoothly, they are doing their job. I initially thought maybe a gear had slipped somewhere, but if it does not move at all it would probably have to be a gear on both trucks.

As Jactal said, it is time for the shell to come off to get a peak at what is and is not happening inside.