Worn Atlas loco wheels? Fixable?

[MK]

This loco was given to me with a busted motor and that if I could fix it I can keep it.  Well I did but I don't know the history of it other than it was used.  I believe it's a SD50.  From the looks of the wheels it looks like it was ran a lot.

The loco runs well but it's the only one I have that seems to pick up dirt on the wheels all the time!  Even on relatively clean tracks.  Then the headlight starts to flicker.  Clean it on a coffee filter and each truck leaves dark lines!  Ran a Kato as a control on the same tracks immediately after and the wheels are clean.  I'm sure another Atlas will do the same.  Heck, I can be using this loco as my cleaning car!   

My other Atlases' don't have wheels that look like this.  So, the question is, does this look like too worn wheels and should they be replaced to solve the frequent cleanings (a pain)?  If yes, how easy it is to replace them?  Will I have gear meshing issues inserting essentially a new gear into a worn (I'm assuming) gear train?  Or should I replace the entire truck?

The lighting on the middle bottom really shows what it's like in real life.

[C855B]

Kato wheelsets should be drop-in*. I buy the six-packs by the dozen for all my old Atlas power, mostly for flanges that don't bounce on the ties on the Code 40 sections of the layout.

* - After fixing the gauge. I find Kato wheelsets to be consistently about 0.010-0.015" narrow.

[MK]

OK, I realize that the dark lines on the coffee filter may be just the nickel oxidation from the tracks and not dirt.  But the head begins to flicker and if I don't clean it soon, the loco starts to hesitate.  Once cleaned on a filter, back to normal.  So whatever it is picking up it's interfering with the electrical pickup.

[Bill H]

Agree with Mike. Cheap replacement with the KATO low profile offset gear replacement wheels.  KATO Part # 932090 (six axles) $8 and all the wheels are replaced. You need to do it.

Cheers,
Bill

[Steveruger45]

Those wheels do look pretty worn.  I would change the wheels for Kato ones for the atlas HTC trucks on the sd50/60. Kato part number 932090.  Available at MB Klein’s (modeltrainstuff) less than $7 for a pack of six. To change the wheel sets remove the truck, hold in both hands and press the wheels up toward you with your fingers while spreading the truck side frames with your thumbs.  The gear tower with wheels will then separate from the side frame. Clean up the left and right side power pick up / axel bearing bits but be sure you remember which side is which as there is a left and a right.  Pop out the wheel sets and push the new ones in and reassemble.
Oh yes, and while you have the trucks apart clean everything with some IPA and an old tooth brush.
Using an Optivisor helps I’ve found too.
the  The black stuff is I believe the nickel silver rails oxide layer.  I got rid of that problem on my garage layout by treating my track with No Ox ID special A. 

[peteski]

I've dealt with Atlas locos with even worse wheel wear.    I also recommend upgrading to the new Kato wheels.  They look very prototypical (low flanges, narrow treads, and nice wheel face profile). They also appear to be made from blackened nickel-silver so they the treads will stay nice and silver (no brass color showing).
I have converted bunch of Atlas locos to Kato wheels.

There is an entire thread devoted to this subject.  I find the Kato wheelset's axles a bit too wide for Atlas trucks, so I press the half-axles in slightly. Then they fit perfectly.  it is all in that thread.
https://www.therailwire.net/forum/index.php?topic=33107.0

Since you will have the trucks apart, it is also perfect time to fully service them. Clean out and lubricate the axle bearing cups, and polish the electric contact nubs and strips.  It wouldn't hurt to clean the gear cases either.  Then the tuneup could be continued up to the chassis - clean and lube the motor and worms.

[MK]

Thanks everyone!  TRW doesn't disappoint!  I was going to ask what's the part number and bam!  Posted twice!  . They are cheap enough at MBK that I'll throw them into my next order or maybe find them at Amherst.

And thanks Steve for the detailed instructions on getting them out.  it will come in handy when the time comes.  Peteski, thanks for that thread link.  I'll read it tomorrow when I have more time.

[central.vermont]

MK there is one very important thing to be aware of. The wheel wipers of these trucks have a left and a right.
It is very hard to tell just by looking at them. This is due to the axle spacing is different. I use a set of digital calipers
to figure them out but you can just compare them to each other and then compare them to the sideframe.
You will know when their right because they will roll freely when you roll them on the workbench. They actually
will snap together with the wrong wipers in but not roll freely, I know this because I've been there done that!!! 

Jon

[MK]

Thanks for the hint Jon.  I'll label them L or R with a Sharpie as I take them off.

Peteski, I read the entire other thread.  I don't have an arbor press but I'm assuming a bench top drill press would work as I can't imagine you need that much force to move those axles.  The only concern I have is how the hell do I know to move the drill press down 0.01"?  Yes, I can measure it with a caliper but that's the final result.  I'm imagining a night more or chasing "Damn, too much!  Oops, too little! Etc." scenario.

Instead of taking each set apart, adjust the axles, reassemble them, measure and repeat (I'm sure I won't get the correct length the first time), I was thinking doing it with everything together and go REALLY slow with the drill press on each side of the axle.

[rrjim1]

I use a HO Slot Car wheel press, much easier to control. 

[MK]

You just gave me a great idea!  I have a gear puller set that I use for my R/C airplanes and helicopters.  I just took a look and I think it can be used to pull the wheel further up on the axle (or push the axle further in depending on how you want to look at it).  I don't even have to disassemble the wheel set as I can do both ends and then probably use my hands to push both into the plastic geared tube to close the gap.

[Lemosteam]

I use a HO Slot Car wheel press, much easier to control.

@rrjim1 Can you share a link?

[randgust]

I've observed through testing that Atlas is using different metallurgy for wheels over time.   The reason you care is a) pickup  b) tractive effort.

They definitely went to a 'harder, slicker' wheel about the time the SD24's came out.  My testing confirmed that the coefficient of traction for those wheels, and the era that followed up through and including the MP15, dropped a lot.  Much slicker wheel, but had good pickup, so I've always intimated that DCC was a major issue with that.   Drove me nuts because what used to take 2 locomotives to get a train up my grades was now up to 4, so I started avoiding Atlas products for main line power that had to handle much of a train.

Kato, meanwhile, uses a different metal on their wheels.  It has a better coefficient of friction on nickel silver - about 25% better for the same locomotive weight.    And excellent pickup.    Consistently.

My latest Atlas GP's are showing a better friction coefficient in testing, so I 'think' they did something lately but can't really prove it yet.

Now, mind you, I'm a tractive effort freak and also DC.  When wheels get worn like that down to the brass you'll see the tractive effort go up about 30% because the brass is softer than the NS plating and gets a better grip.  In the old days, Trix in particular would nearly double in TE when the plating wore off.  My Kato units are fairly well worn, still have excellent TE and pickup, one of them is a rather ancient Kato-built GP35 chassis and just a honey of a runner with no wheel plating left at all.    My Atlas classics - when the wheels wear through I'm seeing the same issues you are - rather erratic performance until the wheels polish up a bit in use again.  But they are also significantly lighter than most Kato frames.

Bottom line, I'm still a firm believer in Kato, and whatever secret sauce they do in wheel and frame metallurgy, so whatever effort you do on wheel swapping is probably worth it.   If you don't care about a 'lifetime runner' I think you can buy replacement trucks from Atlas with new wheels and just live with that.

I had an Atlas SD50 chassis under an FP45 rebuild and I finally got rid of it not because of contact, but because it started the 'clicking' syndrome on those chassis, and I also had a nagging problem speed-matching it with the pair of Kato SD45 chassis despite a liberal dose of diodes to slow it down.  The older SD40-2 Kato chassis has proven to be far superior in every way, just sayin'.

[rrjim1]

@rrjim1 Can you share a link?

Lots of companies out there make them. I made HO slot car Speed Parts for years and sold the company (JW's HO Speed Parts), several years ago and retired.

[MK]

I've observed through testing that Atlas is using different metallurgy for wheels over time.   The reason you care is a) pickup  b) tractive effort.
.
.
.
When wheels get worn like that down to the brass you'll see the tractive effort go up about 30% because the brass is softer than the NS plating and gets a better grip.

I was wondering if Atlas changed their wheel metallurgy over time (probably yes as we're talking about toy manufacturing in China) as none of my other Altases show this kind of wear.  Even the first Atlas that I bought about 10+ years ago.  Then again, like I said earlier, I don't know the history of this loco.  It could have been one of those in a display window running round and round all day.    It did have a busted motor when I replaced.

The loco does pull like an ox!    But the more than frequent wheel cleaning is a pain and it's always at the wrong time, like at a train show.