Best Of *Science* of solving N scale diesel mechanism drivetrain vibration noise?

[randgust]

Wow, glad you found that so I didn't have to tear one apart to prove my point.  But you documented the mystery as well, they've kept the same part number probably, as well as on the motors.   I know on the motors it was completely baffling for a while whether you'd get a slow-speed or a Classic.

I've still got a couple classic chassis left that are worth the crapshoot of ordering new parts to see what I'd get for upgrades.   But my experience so far is that the single biggest improvement they've made is ditching that hex-nut universal.   No more electric razor, no more Beardon Block modifications.   Maybe 20 years of griping on the forums from all of us wasn't a total waste of time after all!

What I'm still not entirely sure if is if they changed the machining in the flywheels to fit the new universal design.   Didn't check that out.   

And while I admire you trying to put a Classic motor back in the new-issue  DCC frame, cradle and all...geez....   I've got a great deal on Takata airbags I could tell you about.

[atsf_arizona]

Wow, glad you found that so I didn't have to tear one apart to prove my point.   

What I'm still not entirely sure if is if they changed the machining in the flywheels to fit the new universal design.........   

Randgust,

I found that the Atlas N scale Santa Fe GP9 Zebra Stripes I checked in my previous post, were released in 2015 July (per https://www.trovestar.com/generic/zoom.php?id=131053 ) :



Thus this loco understandably still has the old style universals as it was released prior to the "circa 2016 change to Kato-style universals".

What we need: 

* Someone who has Atlas GP7/9's released after the change over to these new universals 

* To check the parts diagram in their post-2016 Atlas GP7/9 jewel case and see if it has an updated universal part number for these new style universals:

 



* Also, are there any other Atlas N scale loco's that previously did not have this new universal, that now do?  i.e. the latest July 2016-announced GP35's or newer?

See this URL for when Atlas roadnames were released:  http://archive.atlasrr.com/n-mcloco-archive.html 

The N scale Atlas GP7/9's are listed here:  http://archive.atlasrr.com/NLoco/arc-ngp7.htm )

Anyone have a newer post-2016-released Atlas GP7/9, that could check your parts diagram? 

[woodone]

I just finished doing an older Kato F-3 A & B unit. Sound in the A and DCC non- sound in the B.
This was an older Kato loco. The frame ( split) is almost solid except for room for the motor and drive train. There was a very small and short light board located in the front of the A- No board in the B. The trucks are metal frames with a plastic gear holder which also makes up the side frames. I have a very loud growl at all speeds. The worm bearings are the plastic squares with a bronze bearing insert.
The U joint at the flywheel, is with four small ears that fit into four slots in the flywheel.
I removed the bearing at the flywheel end but that did not help all that much.
I think the noise is from the metal trucks that make contact to the frame.
Don’t see any way to cure that?
I loosened up the two frame halves screws so they are just snug,
The growl is still there no mater what I have tried to this point?

[rrjim1]

I just ordered some of the new GP7/9 worm gear assemblies with the new universals on ebay. I have seen these on other new Atlas locos but there to long to fit a GP7/9. On the U23B page the universal is list as two parts, the ball universal and middle universal.

[EmdFan]

I'm glad this thread resurfaced, I had forgotten about it.

I've been trying to work this out myself for a long time. The problem first cropped up for me in the 90s when the Atlas/Kato GP30s and GP35s came in. I was working for Atlas doing locomotive repairs at the time, and was baffled that I could not build a chassis from parts and not have it noisy. I was a pretty good repair guy, and thought I knew these things well enough. Ron B and I went back and forth over it, and that was when he came up with the bearing block trick.

I'm back at Atlas in a different capacity, but I still see this problem surface on a semi regular basis. We recently received two batches of pre production samples, both being four axle Geeps. One batch is quieter than the other, despite the chassis being the same. I am going to take one sample from each batch and on my own time see if I can get it figured out. The noisier of the two is still acceptable, but I can't help but want to see if I can figure anything out.

I will be sure to post my findings.

I like the idea of getting away from the split chassis design eventually. The chassis that are more like shrunk down HO chassis (BLI, ST etc) seems like a more stable platform. But for now any legacy locos will have to keep the current design.

Happy Holidays to all.

Steve W

[atsf_arizona]

I'm glad this thread resurfaced, I had forgotten about it.

I've been trying to work this out myself for a long time. The problem first cropped up for me in the 90s when the Atlas/Kato GP30s and GP35s came in. I was working for Atlas doing locomotive repairs at the time, and was baffled that I could not build a chassis from parts and not have it noisy. I was a pretty good repair guy, and thought I knew these things well enough. Ron B and I went back and forth over it, and that was when he came up with the bearing block trick.

I'm back at Atlas in a different capacity, but I still see this problem surface on a semi regular basis. We recently received two batches of pre production samples, both being four axle Geeps. One batch is quieter than the other, despite the chassis being the same. I am going to take one sample from each batch and on my own time see if I can get it figured out. The noisier of the two is still acceptable, but I can't help but want to see if I can figure anything out.

I will be sure to post my findings.

Happy Holidays to all.

Steve W

Steve W, thx very much for participating.  We're looking forward to hearing what you may find.    Happy Holidays.

[CRL]

Sounds like a left Twix vs right Twix problem.

[EmdFan]

Steve W, thx very much for participating.  We're looking forward to hearing what you may find.    Happy Holidays.

Thanks John, and thanks for your efforts too, you've put a lot of time into this.

Steve W

[Steveruger45]

After doing some more “de-coffee-grindering” on some four axle Atlas locos, including some old Classic GP’s, Master GP’s and B23-7’s and B40-8’s, I have noticed in addition to all stated before on the worms and universals and bearing blocks that some of the truck gear towers and gears can be a problem area.
Namely the small intermediate truck gears can move, canted from true longitudinal, when under load.  Either the axle ends of theses gears appear a little too short and/or the holes for these axle ends in the gear tower are worn or a little too big.  Changing gear towers and gears fixed it for me. 

[u18b]

I'm glad this thread resurfaced, I had forgotten about it.

I've been trying to work this out myself for a long time. The problem first cropped up for me in the 90s when the Atlas/Kato GP30s and GP35s came in. I was working for Atlas doing locomotive repairs at the time, and was baffled that I could not build a chassis from parts and not have it noisy. I was a pretty good repair guy, and thought I knew these things well enough. Ron B and I went back and forth over it, and that was when he came up with the bearing block trick.

I'm back at Atlas in a different capacity, but I still see this problem surface on a semi regular basis. We recently received two batches of pre production samples, both being four axle Geeps. One batch is quieter than the other, despite the chassis being the same. I am going to take one sample from each batch and on my own time see if I can get it figured out. The noisier of the two is still acceptable, but I can't help but want to see if I can figure anything out.

I will be sure to post my findings.

I like the idea of getting away from the split chassis design eventually. The chassis that are more like shrunk down HO chassis (BLI, ST etc) seems like a more stable platform. But for now any legacy locos will have to keep the current design.

Happy Holidays to all.

Steve W

Hi Steve,

I know you can't reveal too much....   but since you posted...

Does this new Geep have a floating universal?
Of a shaft situation like the old way- hex nut on the wormshaft, inserted into the flywheel?

Seems like a saw a 4 axle Atlas loco a while back (the GP39-2?) that had a new floating u-joint in it.

[645diesel]

i read most of this thread as my long stored Atlas units are now making "the noise"

i took the U25B apart and found a very waxy grease, boo.  i have gathered that i should clean that away and use a fresh lubricant.  do i use a grease like product (Labelle 106) on the worm gear/truck gears or am i to convert to a liquid (Labelle 108) for all friction surfaces, not just the plastic worm gear bearings?

TLDR; can and should i clean the now waxy OEM grease away and switch to Labelle 108 for all drive train lubrication?

[randgust]

The newest GP7 I got a little while back has that ball and cup universal in it and it is just...silent.   And it took some digging but I found more of those parts online, even though I literally got a 'we don't have those' email back from Atlas when I asked them the question.

I'm in the process of retroactively installing those universals in my older units.  First one went to an Atlas-Kato GP35 that sounded like a razor, it's now completely silent.   While the Beardon Block works most of the time and Ron gets the credit for discovering the problem, John may get some credit for spurring the reaction.  While I'm not saying that lubrication won't fix your noise problem, if it doesn't there are other ways to attack the problem.    Lubrication will fix the Kato Screech for a long time, for sure.

[u18b]

i read most of this thread as my long stored Atlas units are now making "the noise"

i took the U25B apart and found a very waxy grease, boo.  i have gathered that i should clean that away and use a fresh lubricant.  do i use a grease like product (Labelle 106) on the worm gear/truck gears or am i to convert to a liquid (Labelle 108) for all friction surfaces, not just the plastic worm gear bearings?

TLDR; can and should i clean the now waxy OEM grease away and switch to Labelle 108 for all drive train lubrication?

Yes.  That's what I would do.

[peteski]

Yes.  That's what I would do.

Yes, a complete cleaning and full tune-up is an excellent idea. Plus it is fun completely taking model locos apart, isn't it? 

Yes I know it is a steam loco - those are even more fun than the simple Diesel models.

[kiwi_al]

Yes, a complete cleaning and full tune-up is an excellent idea. Plus it is fun completely taking model locos apart, isn't it? 

Yes I know it is a steam loco - those are even more fun than the simple Diesel models.

Slightly off topic, I only know one person who'd do that to a Steam Loco, the Victor is strong in you young fella!