New Atlas GP39 sounds like an Athearn Blue Box

Got the above at a train show last week and it sounded horrible right away. Lubed it up as best as I could and it did quiet down somewhat. Silent in reverse but noisy going forward. I tood the body off again and have been running it constantly to beak in and it got where it got quiet. However when I put the body back on I hear the blue box type noise again. Any thoughts on this and what I can do to get her quieted down?

Bruce

Sounds like the body shell is acting just like a drum shell, by amplifying the drive train noise like a drum shell amplifies the drum head.

I know Atlas has just about every nook and cranny stuffed on most their units, so adding fillers inside the body might not be feasible.

Usually the best way to quiet them down is b adding some foam inside to act as a sound deadening agent. But if there isn’t enough room to do so, I’m not sure where to suggest going from there… Unless you would be open to onboard sound to mask it?

Is it possible that either the shell or the motor is loose or out of alignment? It sounds to me like one, or even both of those things could be the culprit and the torque of the motor causes it to either rub or vibrate when moving forward. I’d go over it with a fine tooth comb and see if that’s the problem. Another option would be to call Atlas and ask. Their customer service is quite good.

Everything looked ok but I will try your suggestion and look again at the body and the motor, although I have been running it constantly today and it does seem somewhat better. If its just break in issues it sure is taking a long time to resolve.

I think those were released in mid to late 2009 ? So if you bought NOS, it’s been sitting a while. You might want to check the lube in the trucks, gear tower, and the worm gear. It might be a little “stiff” from sitting.

Mike.

Try running the motor out of the engine. If you feel much vibration, it may have an off-balance flywheel. That can cause a low frequency humming similar to the old Athearn growl.

After lubing some more and running it almost non stop for 3 hrs it is now blue box noise free. This is the most stubborn loco from Atlas I have ever had, most are great right out of the box or only take a few minutes of run time to break in. At least its now ready for service. Thanks for all the help and comments.

Bruce

That’s what happens when an Alco guy buys EMD… [(-D]

–Randy

You got that right lol