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

[NtheBasement]

What, the armatures aren't unwound? 

Reassembly in large scale is scary enough.  https://www.youtube.com/watch?v=z_-LDE6hJHc

[CRL]

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.

All that skill and it still has a Rapido coupler. 

Yeah, I know it’s a European model. 

[peteski]

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

Yes, Victor Miranda.  I know him well, going way back to the old Atlas forum.  He participated here for a while, before going silent. I've heard he does not really participate in any online forums nowadays, which is not a bad idea at all.

[nscalbitz]

Shouldn't this thread be escalated to a 'Best of' by now...?

[mike_lawyer]

Yes, Victor Miranda.  I know him well, going way back to the old Atlas forum.  He participated here for a while, before going silent. I've heard he does not really participate in any online forums nowadays, which is not a bad idea at all.

He participates over on the N-scale.net forum.  Not sure why he does not stop over here, his knowledge is missed.

[u18b]

I also think this thread should be elevated to Best Of.

Almost 24,000 views at this point.  very helpful info from a collection of great work from this community.

Best Of would make this easier to find this valuable info in the future.

[peteski]

I also think this thread should be elevated to Best Of.

Almost 24,000 views at this point.  very helpful info from a collection of great work from this community.

Best Of would make this easier to find this valuable info in the future.

I agree.  I'll notify the moderators.

[atsf_arizona]

Hi, all,

Welcome to 2025.  Now that I'm retired (and back to doing some modelling).... I was reviewing this great thread.   And applying what it documents
to some new projects.   Thanks to all of you.   It's satisfying to rehabilitate noisy mechanisms......

I was wondering, Randgust...
referencing these Replies earlier in this thread:

Page 13, replies #193, #194
Page 14, replies #195, #196, #204, #205

question:

==> Did we ever figure out if Atlas has a new part number is for the new GP7/9 universal joints, that you/we referred to / identified earlier in this replies in this thread? <==

==> Did we ever figure out if the 2016 and later Atlas GP7/9 or other locos, updated their parts sheet included with the loco, to identify this new universal with a new part number?  <==

In those replies, Randgust identified that starting in 2016, Atlas GP7/9 started using a new universal joint in these mechanisms, that really caused a much
more silent running.   Randgust  reported in those replies, that he was able to use these to quiet down not only noisy Atlas GP7/9, but also quiet the
older (sometimes problematic)  Atlas/Kato GP30/GP35 mechanisms.

Here's a picture of the new universal.  If there is a new part number, I'd like to order some of these from Atlas :



Thx, if anyone has input / knowledge on this topic / question from years ago.   

 


P.S.  I did order a new Atlas Santa Fe GP7 Torpedo Tube (just released recently 4Q2024), so that I can check out the above question for myself. 
I'll report back here, what I find.

[Brian M]

John,
Take a look at the exploded parts diagram of the GP-9TT on their website:
https://download.atlasrr.com/PartsPDF/NScale/NGP9TTLoco.pdf

Looks like it might be part 485103 for the worm and shaft.

-Brian.

[atsf_arizona]

Brian M,

Thx and you're right on.

While the older Atlas GP7, GP9 parts diagrams still show the older universal.... the Atlas GP9 Torpedo Tube parts diagram (https://download.atlasrr.com/PartsPDF/NScale/NGP9TTLoco.pdf) shows these newer universals with their part numbers. 

Comparing the new part number diagram on the left, with the older one on the right:


(URL to bigger copy of this image here: https://pbase.com/atsf_arizona/image/175170605  )

In order to use the new universal to try retro-fitting it to older Atlas N scale GP7/9 or GP30/35, it seems the appropriate thing to do, is order the whole worm and shaft part number 485103.

Note that the old universal part number 480003 / worm+shaft part number 480103 combo, the shaft was longer as it had to reach all the way to the flywheel.  Thus, just ordering the newer ball joint/universal, won't be the right method, they'd not fit onto the older too-long shaft.  So, I am assuming we should order the new entire worm/shaft part number.

Here's side by side picture of what I mean.  On left is the new Atlas N scale GP7/9 worm-shaft p/n 485103.  On the right is the old Atlas part number 480103:



Now, I was on the Atlas Parts website.... and I haven't yet figured out how to find this part number 485103 worm/shaft, and order it.   Searching for "485103" came up with no hits.  (Searching for the older 480103, did result in a hit on the old worm-shaft part).

I sent a 'Contact' request email via Atlas Support option on their website, I asked if there's a way to specify that part number, and order some of these newer worm/shafts.  Hopefully this week I will get a reply.

If I can get some of these, then I'll try these out on my older Atlas locos... and see where and if they fit, on what locos..... and report what the results are. 

I'll keep you all updated on what happens.

[Mark5]

Now, I was on the Atlas Parts website.... and I haven't yet figured out how to find this part number 485103 worm/shaft, and order it.   Searching for "485103" came up with no hits.  (Searching for the older 480103, did result in a hit on the old worm-shaft part).

I sent a 'Contact' request email via Atlas Support option on their website, I asked if there's a way to specify that part number, and order some of these newer worm/shafts.  Hopefully this week I will get a reply.

If I can get some of these, then I'll try these out on my older Atlas locos... and see where and if they fit, on what locos..... and report what the results are. 

I'll keep you all updated on what happens.

Following with interest - appreciate this!

Mark

[atsf_arizona]

I received a prompt reply from Atlas Customer Support 1 day after sent the inquiry, regarding whether the Part Number 485103 "new type of worm/shaft" is available to order as a part.

==========================

Hello, Mr. Sing,

Unfortunately we are sold out of that part (JS:  part number 485103).

I don’t know when we’ll be getting anymore in.

I don’t think we use that particular worm anymore.

Steve

Customer Service Manager
Atlas Model Railroad Co

=======================


JS:  I have just ordered and received a new Atlas GP7TT.  When I have time, I will examine the new mechanism and see what universal joint, the new sound-ready mechanism uses.  The new parts diagram says it uses a ball-joint universal that looks similar to the above p/n 485103, but it has different part numbers:

==>   AF96050702  is the ball joint side that goes into the flywheel
==>   AF9607B03    is the corresponding worm/shaft assembly that mates to this ball joint

Here's a picture of the new 2024 Atlas GP7/GP9 parts diagram for the new 2024 sound-ready mechanism (AFAIK as of 1/15/2025, this isn't yet up on the Atlas Parts website yet....):



NOTE:  I did notice, that my loco was assembled at the factory with the shell on such that speaker is at the *rear* of the assembled loco, *not* at the front as the above parts diagram implies. 
Is this the case with all of you who have one of these new-mechanism Atlas GP7/9's?   
If so, the above parts diagram, is incorrect as it shows the speaker is under the front of the loco.   
I did try to assemble the shell on the other way, so that my speaker would be at the front, but it seemed to not want to go on that way..... any others have same experience?
------------------------------------------------------

I'll report back here if I can find any more info about whether this new part numbers have any chancel of being a replacement for the Atlas "worm gear" p/n 485103 referred to above (this sidebar discussion of a new more quiet universal joint was added to this thread in the post by Randgust (post #193 on Dec 22, 2019)).
 
Since the newer 2024 sound-ready mechanism is so different than the older mechanism, let's assume these two parts are different, unless we find out otherwise. 

In the meantime, it may be moot, because I did try to find this above new part number at the shop.atlasrr.com webpage, but (as of January 15, 2025) these new part numbers AF96050702 and AF9607B03 do not come up either in the list of Master GP7/9 parts available for order, nor in the Parts search.

(The new generation Atlas GP7/GP9 sound-ready mechanism can be seen here at Spookshow's GP7/9 Atlas webpage: http://www.spookshow.net/loco/atlasgp79.html )

[tehachapifan]

I don't know if it's been mentioned before (too lazy to read thru all the pages), but one definite culprit for excess noise in N scale locos is there being too deep of a "bite" between the worm gear and the top truck tower gear I believe causing vibration. I had a 1st run Atlas N VO-1000 (the one with the weird, glossy frame) and 1st run Athearn N F50PHI that both made terrible growling noises as speed was increased. I managed to make adjustments on both (no easy task!) that allowed the worm to raise up ever so slightly and now both run and sound way, way better. The VO is almost completely silent now and the F59 is light years better than it was but still a tad noisy.

Edit: I believe there was a kit from Atlas to fix the noise in the VO-1000 but I missed out on those. I'm guessing these kits addressed the deep bite issue as well.

[Jim Starbuck]

I don't know if it's been mentioned before (too lazy to read thru all the pages), but one definite culprit for excess noise in N scale locos is there being too deep of a "bite" between the worm gear and the top truck tower gear I believe causing vibration. I had a 1st run Atlas N VO-1000 (the one with the weird, glossy frame) and 1st run Athearn N F50PHI that both made terrible growling noises as speed was increased. I managed to make adjustments on both (no easy task!) that allowed the worm to raise up ever so slightly and now both run and sound way, way better. The VO is almost completely silent now and the F59 is light years better than it was but still a tad noisy.

Edit: I believe there was a kit from Atlas to fix the noise in the VO-1000 but I missed out on those. I'm guessing these kits addressed the deep bite issue as well.

My findings are the same as Russ. When setting up a remotor or scratchbuilt mech I try to get the worm to run about half the depth of the tower worm gear teeth.
When upgrading the LifeLike switchers with brass worms I also use Atlas worms over Kato because they are a bit smaller diameter which draws the worm up out of the root of the worm gear and they run near silent. I’ve found this slack also helps when the truck pivots on tight radius curves.

Jim

[atsf_arizona]

Techachapifan and JimStarbuck,

Yes, your point is right on, we found back in replies #74, #102, and #160 on page 11 of this thread (January 7, 2017! - direct link here to reply #160: https://www.therailwire.net/forum/index.php?topic=40758.msg507010#msg507010)..... 

That this "bottoming out of the gear teeth on the worm gear" issue,  was the exact reason causing the noise on the noisy Intermountain N scale Tunnel Motor loco mechanisms, that started this thread back on Dec 25, 2016 (8 years ago).

Lots of info and discussion on this topic at the URL cross-link to reply #160.

Thx for reminding us all, to always check for this "bottoming out" issue, as a noise reason!