Hi CrawlHard; I also learned that DCC is more voltage sensitive than DC ops. That all DCC crossings, switches and turnouts can be electrical problem areas... especially at slower speeds (rail-yards). I use Labelle 105 Track Cleaner to clean the rails at any location with plastic frogs. Its dielectric and will improve Loco operation through the crossing, etc. 

Hi JWard... Good information on Athearn wheels, many thanks. Also points out need to do Loco maintenance annually, to include cleaning wheels. 

Hi Benjamen; Great site, thanks. I've replaced about 10 split axle gears on Proto 2000 locos with complete drop in wheel/gear units ($$$). Wish I had kept the old split gears... now that you have taught me how to repair the split gear itself. I learn something new everyday... thanks again.

Hi JWard, This shell noise occurs in both DC and DCC. It goes away when shell is removed in both DC and DCC. Turning DCC sound on/off doesn't matter, sound happens with shell on... goes away with shell off.

Hi Benjamen: Wonderful link (thanks) with lots of information to digest. Will read it 2-3 times to get whole picture of problem and solutions, thanks again.
I like that HO Stnd Gauge and coupler photo. I check all my rolling stock when I get them, or complete a kit build, and also after any maintenance work. To date I've been lucky and a simple knuckle coupler swap-out as always worked. I keep a stock of EZ Mate Mark II couplers in under, over and center shank, with both medium and long shank. My F3A, F7A and F9A I always need to use "long shank" to make uncoupling easier.   

Hi Quentin; I really like Bachmann EZ-Track, EZ-Command, Silver series railcars and their selection of EZ-Mate knuckle couplers... Like Benjamen, I've had NIB loco issues (mostly minor) with their diesels about 50% of the time. The major issue for my slow yard-speed use is the LOUD harmonic noise.

As to other mfr locos I stick with their top-line products Proto, Genesis, Master Gold, etc... I also search for older NIB sales... Getting a NIB $300. DCC loco for $125. or a NIB $200. DCC-Ready for $90. I just might 'bite' and reel it into my loco fleet (CB&Q, GN, NP). I'm always in the market for NIB switcher, road-switchers and GPs. I have 18R curves, so I keep length of rolling stock and locos to a minimum. I model freight and avoid Pax cars. My wife runs mostly "wine" boxcars and "wine" tankers. It's a great hobby for nasty weather days to stay indoors... like today we have freezing FOG. Good wx I'm on the tractor in the wood lot, or using disc or brush hog.
Happiness is a way of living life daily... so keep smiling...

Hi Benjamen; Wow NIB with [1]motors out of tolerance, [2]noisy gear boxes, and [3]cracked drive shaft universal joints. That points to a much larger issue... total lack of quality control on the production line. When you buy brand NIB locomotives needing immediate replacement of motors, gear boxes and universal joints that is nasty and unacceptable. The production last inspection and test run, should be catching 99% of those parts and workmanship failures.
Thanks for the heads-up, I'll be looking for your 3 issues when I get to checking Len's idea on proper positioning of universal on the motor shaft (could be cracked too).

I also usually spend the first 1-2 hours of any new loco in a break-in fast/slow/fast/slow forward/reverse/forward/reverse mode. To date (not counting multiple harmonic noise issues) out of 30+ new locos, only one is still has an operational problem. At low RMP, slow jerky movement for first 20-30 feet, then it goes smooth and doubles the speed (without me increasing controller voltage).

I don't mind routine maintenance issues, and I've done Oops myself, needing repair. But having NIB part failures needing repair on 20% of brand new locomotives is unacceptable and costly.  Keep smiling...

Hi NerdlyNate;
Welcome to a great hobby... best to learn it one step at a time... learn something new every day and build a solid foundation of knowledge. Trainman and Yard Master have covered DCC (digital) basics and just touched on DC (analog) systems. You'll need to understand both and when locos are interchangeable. DCC locos will run on DC too... but need to have DC turned "on" in DCC programing. [Most DCC locos come with DC ops already turned "on"]

Visit NMRA to learn DCC standards. Understand that DC locos that are "DCC Ready" come in two flavors... [1] 'plug and play' simply plug a decoder into a socket for 8Pin, 21Pin, 18NextPin, etc or [2] requires mini (micro) soldering the decoder and sound speaker. You have to read the loco instructions to understand which DCC Ready the mfr means... plug-in or soldering. Also industry standard is that NIB DCC locos come with a DCC Loco "address" of "3".

Learn what DCC "Functions" are (lights, sounds like bell and horns, etc) and that EZ Command DCC controller will handle up to 9 DCC locos. It will play sounds like Bell and Horn, turn lights and sound on/off, etc. The EZ Command does not program DCC locos, like higher level DCC Controllers do. But, it allows you to change DCC Loco "address" to a number 1-9.  Three years ago, I was where you are now... it's a fun trip into running DCC...
Enjoy it and keep smiling. 

Thanks Len, I got it and will check when I get a chance. Next two days I'm busy with other family stuff. Your idea and drive train solution, might just be (mfr oops) reality, for many strange Bachmann diesel loco shell harmonic noises.

I noticed Bachmann trucks are designed to "touch the chassis" on a single point (both left and right side). The drive train universal on motor shaft would "transmit sound" through (one or both) trucks and into the chassis.
W/O the shell on = "no noise". But with the shell on the chassis, it could very easily transmit noise into the side of the shell, making a harmonic sounding-board. Interesting concept to explore. Thanks again...

Hi Len... OK you might have found the issue, thanks. Let me see if I understand your description of the problem...
From the motor, the shaft leaves the motor and goes into the flywheel. The problem is NOT with that shaft or the flywheel location on it.
The shaft exits the flywheel and goes to the universal connector (usually plastic) which slides onto the motor shaft... and this plastic piece might be too close to the flywheel. That would mean I need to increase distance between the flywheel and that universal shaft.
Is that the correct picture???
If I have it backwards... then that universal piece is too close to the flywheel and must be farther from the flywheel (further out the shaft towards the truck). So I would increase distance between flywheel and universal piece (on the shaft).
I'll take a look tomorrow... that means one OR both universals (front and rear) might be out of spec for proper functioning.

Hi Quentin; yep tried it with light foam and heavy foam cut to fit tight inside the shell, hoping to deaden the shell harmonics. Some suggested using caulking inside the shell to deaden harmonics.

Hi Len; Shells are good fits, no warping, I tried 1,2,3 layers of that Blue EZ removable painters tape on corners and edge of elec. mother board in case they touched the shell. No wires touching. Funny part is these locos run beautiful without the shell (a low motor hummmmmm)... only with the shell on... do they make any noise, more of a growl.
Other mfr have figured out 'low sound' smooth hummmmmmm... running locos. About half my Bachmann locos are too noisy and that one old Atlas... but it's much quieter than these two Bachmanns. I've read many other forums about engine noise... but those are mechanical and electrical issues needing repair. These Bachmanns run perfect w/o the shell... meaning it is not the motor, running gear, etc.

I have NIB Bachman HO S4 and GP30 with nasty LOUD motor noise when they run. With shells removed... bare chassis they run like a finely tuned sewing machine with almost silent running. Without their shells I just hear very low motor hummmmm, and metal wheels on rails and a lovely (to me) 'click-click' when crossing rail joints. Put shells back on and that LOUD nasty motor noise returns.
Obviously the shell itself is becoming a sounding board, which then amplifies the motor noise (by a factor of 10 or 20). I'm not the first to have this situation... Has anyone found the primary source of the problem and what was your solution?

Bach-Man what say you??? [Is it a design or mfr issue I can fix?] Never had this issue with Walthers Mainline or Proto, Athearn Genesis or Kato. I have one Atlas with similar "noise by shell" problem, but it's volume is 10x less than inherent Bachmann noise...
I've posted this question on other forums and gotten weird answers from 'turn UP the X-mas music' to 'wear ear plugs'. Nobody knows the source or reason why Bachmann shells increase motor noise by 10-20 times. And nobody has any idea how to quiet them down. Bachmann designers might know the solution and should share it with Bachmann purchasers. 
I only run yard speed and double yard speed on my layout... so any LOUD motor noise is very unpleasant... and unnecessary.

Excellent... please let me know how it compares to HO during your test. I run HO 18" and 22" radius curves, not sure what equivalent TT radius would be (someday I'll run the numbers). Good luck. TT track on 4'x8' set-up could be huge compared to my 64' of HO track on 4'x8'. 

Hi JWard; Yep, just checked and my DH166PS has a separate 'male' 9Pin to plug into a 9Pin socket. Should work OK. Either way, I have both the 'male' 8Pin and 9Pin. Time to get out my I-Fix-It tiny tools and get this U28B on the rails... 

Hi Trainman; Nice video thanks. I have 2 Athearn Genesis with Tsunami-2 DCC and really like them (GP-18 and F7A). Their CVs are nicely designed and give good performance once set. Never had a problem with them. My Quantum DCC are more switch induced back to Mfr default settings. Never had that occur with Tsunami-2.

Hi Trainman; Wow, you're really into era proto ops... DCC Steam is nifty for sure. I'm doing early era diesel, half DC and half DCC. The grandkids like Diesel spotting, looking for older diesels. We have Weyerhaeuser SW-9 switchers here in Longview. I didn't electrify my switches as back then all switches where 'manual' so I have all manual switching... I assume steam locos = manual switching like the old days. The grandkids have taken many steam train rides around Pacific NW, and they hit annual model train weekend at the local Train Museum. Life is good... Keep smiling...