Any suggestions on how to quiet a Bachmann Plus GP35?

[jbrock27]

The faster the speed, the more a "buzz" noise is produced by my loco.  It is lubed and oiled, so it is not a dry problem.  I have also put black electrical tape where ever I can between the shell and frame in a effort to buffer vibration between the frame and shell, but to little avail.  I have run it repeatedly with the the shell off to watch the mechanics and everything looks fine-no wobble, no binding, etc.  Whatever is causing the noise, certainly appears to be resonating through the shell.

Thanks for the help.

[Doneldon]

jb-

It sounds like you're saying that your loco quiets down when the shell is off. If so,
try some plastic-safe caulk or adhesive on the inside of the shell in several places.
Use something goopy, like caulk, to muffle the shell's vibration. Make sure that
you'll have clearance on the inside between what you apply to the shell and the
inner works.

                         -- D

[Stephen D. Richards]

Are you running it DC on a DCC track?  It might be the motor hum.  If it's more than just the hum, is the drive shaft at an angle that appears to be excessive?  Stephen

[jbrock27]

Yes D, it does run quieter w/the shell off.  And at slow crawl speeds, very quiet.  Thank you for the suggestion.  In doing that, would I ever be able to take the shell off again?

Stephen-I am running it DC.  I did wonder if it is the motor or flywheels, and have watched the flywheels turn with the shell off.  They don't hit the frame or appear to wobble.  The more RPMs, the motor turns, the more you can see both dog bones go from running truly straight to having a little more of an "elliptical orbit" to them as they turn.  The motor though looks like it is level and definitely is not loose.  I have taken  the motor out and run it by itself.  The higher RPMs, the more vibration it makes; but there is nothing visible that the motor does that would indicate why it is vibrating more.

[jonathan]

jbrock,

I once had some serious buzzing from a F40PH at higher rpms. I put a super tiny drop of conductalube right where the motor shaft comes out of the motor, on both sides.  This helped a little.  Ultimately, the more I ran it, the quieter the locomotive became, to the point where it no longer buzzes.

Does your noise sound more like a buzzing?

Regards,

Jonathan

[jbrock27]

Yes it does Jonathan.  That is the best word I have used to decribe it.  Buzz, as opposed to a "growl" or "clunk"....

[Doneldon]

Yes D, it does run quieter w/the shell off.  And at slow crawl speeds, very quiet.  Thank you for the suggestion.  In doing that, would I ever be able to take the shell off again?

jb-

Yes, no problem. Let the goo cure before you put the shell back on and the goo will damp the vibrations but let you easily remove the shell.

                      -- D

[jbrock27]

One more thought that I will put out there before going the route of using the caulk.

     -If I do, that then I am treating the symptom (vibration) as opposed to treating the condition that is causing the vibration. 

Anyone have thoughts as to what is causing the vibration in the first place, that is then being heard through the shell bc of vibration?  And better question, how to go about solving that condition?

Thanks all.

[Doneldon]

jb-

With the situation you describe -- vibration noises with the shell on but not with the shell off -- the symptom is the problem. A tight-fitting shell probably wouldn't vibrate but that's a difficult fix unless you want to drill and tap so you can screw the shell to the frame. There will always be a tendency for comparatively thin shells to resonate to the normal vibrations and sounds of the mechanicals. This is noticably worse with loose shells. So dampening the shell's ability to vibrate should quell most of the noise you are hearing and it might even dampen some of the normal resonance.

Let me congratulate you on an excellent and appropriate question. We often throw out suggestions on this board without any
explanation about why something works. You did all of us a service by reminding us that, sometimes at least, more is needed than
a simple answer.

                                  -- D

[jbrock27]

Thank you again D for the suggestion AND the kind words.

[jbrock27]

...and D-just want to clarify again, that the motor itself, does have increased vibration, with higher RPMs, but don't know why.  I do know it does this, bc like I pointed out to "Stephen", when I have take the motor out of the frame and run it on it's own, it vibrates with increased RPMs.

Have you ever used the goo trick you suggested?

Looked in both Home Depot and Walfart last night for goo.  Not sure if kitchen/ bath silicone will do the trick or not.  When I was in H.D., the person suggested I use stuff that looks like blue putty, like "fun tack" used to look like.

[Doneldon]

jb-

Yes, I've used this trick but not often as I mainly do steam, an artifact of being an old fart.

Any goop which is marked "safe for plastic" or foam insultion is good. Liquid Nails for projects is one such and a good choice because you can buy a small tube or a large tube such as you'd use in a caulking gun. What you want is something that stays flexible because that will, in essence, soak up the vibration. I've never tried to use fun tack for this purpose because I don't like the way it doesn't work for what it's supposed to do. I used it for hanging posters and such for my sons and it always left an oil spot which even bled through new paint. I had to seal with Zins before I could paint again.

There is a glue called "Goo." It's a strong, flexible product made by Walthers. I suppose it would work but It's pretty expensive to be
just a sound suppressor. Walthers packed it with their wood and metal passenger car kits at least as long ago as the 1950s. I still
use it from time to time, especially for wood to metal bonds. I purchased an old Walthers kit three or so years ago and it had its
Goo tube. Amazingly, it was still good!

By the way, the motors in current modles tend to have very high rpms compared to those used years ago. That's how they achieve
such smooth running characteristics.

                                                             -- D

[jbrock27]

I had figured you and some of the other frequent posters to be steam guys.  Cool!

Yes, I remember the oily spots from fun tack!
And yes, Bin or Zinsser needed as a stain blocker.  Thanks for giving me a few more specifics on what to try should I give it a shot. 
I hear you loud and clear.  Right now, I have the GP35 disasembled (again).  I am cleaning the trucks and gears, wheels and will take the frame apart again to see if I can do any more work on the motor to cut the vibration down.  Also received some new coupler boxes to mount because the old ones were too low.  I think I will try wrapping more electrical tape around the magnet part of the motor to "cushion" it in the frame and see what happens from there.  For $25 I hate to just send it to BACHMANN, just to possibly get it back "cured" which does not turn out to be a cure at all.