Atlas Locos vs. Code 40 - Newer vs. Older?

[C855B]

Discovered something interesting this evening in powering-up the first sections of Code 40 (M.E.) on the layout - the Atlas 6-axle power (C630, SD24) I've been using for testing trackwork hits the spike heads. These are somewhat newer models, DCC-capable chassis and all that, but that said, they're probably five or six years old. In comparison, the Bachmann DDA40X and 44-Tonner are fine. What puzzles me is the Atlas S-2 is OK, as well... runs great, as a matter of fact.

So I guess what I'm asking here is whether recent re-issues of the C628/C630 and SD24/SD26 have different tooling for the wheels, with profiles closer to the S-2. If so, then I have a parts order to make, if not, then is there a solution that doesn't involve chucking wheels in a Dremel?

[C855B]

But wait, there's more!

Older Atlas 4-axle (U25B) hits the spikes. Older Kato 6-axle (SD40, non-DCC compatible) hits the spikes. Newer Kato 6-axle (U30C re-issue, DCC chassis) does NOT hit the spikes, Kato NW2 is OK, too.

I have a boatload of power I picked-up in the late '90s and early '00s. I guess the question now is whether I am doomed to replace it all.

[Scottl]

Or not install code 40...

[C855B]

Or create an operating rule that certain classes of power are prohibited on said trackage. 

The Code 40 looks good and is a nice contrast to the mainline. Ideally, I wouldn't mind replacing wheelsets if "modern" wheelsets are available and compatible with the older trucks. Or even NWSL wheels, which is what I am doing on Con-Cor U50s.

[peteski]

Kato did change their wheels (not sure when). The new wheels are semi-scale (and look great). They have much narrower tread, smaller flanges, and a more correct dished wheel faces.  Kato sells those wheelsets so you can retrofit them into your older models. They also fit Atlas locos. But the pointed half-axle ends stick out a bit too far on those new wheelsets when installed in the older models. I had to push them in a bit (in my handy mini arbor press).

http://www.modeltrainstuff.com/Kato-N-Low-Profile-Geared-Wheelsets-p/kat-932090.htm

[C855B]

Most excellent! Thanks, Pete. I knew somebody here would have an answer.

I agree, the wheels on the new U30C (and NW2) look great, so it's super this happens to be the solution for the older stuff. I would guess since the new profile was on the first release of the NW2, that would put them ~2007 if not earlier.

[C855B]

... the pointed half-axle ends stick out a bit too far on those new wheelsets when installed in the older models. I had to push them in a bit (in my handy mini arbor press) ...

Obviously I'll see this for myself when they arrive, but you pushed the axle ends in... without altering the gauge? Seems counterintuitive.

[Missaberoad]

Most excellent! Thanks, Pete. I knew somebody here would have an answer.

I agree, the wheels on the new U30C (and NW2) look great, so it's super this happens to be the solution for the older stuff. I would guess since the new profile was on the first release of the NW2, that would put them ~2007 if not earlier.

2007 sounds right, I first saw them on the first run of mid production SD40-2s. 

[peteski]

Obviously I'll see this for myself when they arrive, but you pushed the axle ends in... without altering the gauge? Seems counterintuitive.

This was discussed back in 2014.    Full discussion (recommended):
https://www.therailwire.net/forum/index.php?topic=33107

Picture from my explanation (because for some reason this was difficult for some to comprehend): 

[C855B]

Easy 'nuff. Thanks.

[Chris333]

Any one know if these Kato wheels fit in Life Like locomotives?

[C855B]

Which Life-Like models do you need to check? I have old and new GP20s, FAs and C424s. I think some E8s rattling around in a box, too. Never really looked to see if they have common wheelsets, but I have to wonder given the spread of years between all these if there aren't differences.

EDIT: At first blush, a definite maybe. The GP20s, FAs, C424s and E8s all have offset gears and cone axles. The SW8/9/1000/1200 axles have centered gears, so the Kato wheelsets won't be a drop-in; I'll check if the gear tube is compatible and can be swapped. Haven't verified tooth pitch(es) yet.

My new stash of Kato wheelsets is at the layout building, so I don't have eyes on at the moment. I have the locos bundled to take over there tomorrow to check.

[Chris333]

Was looking at the FA/B1's. They make it around like 90% of my layout fine, but rub spike heads on the other 10%.

[C855B]

I converted a split-frame FA somewhat successfully. I had to follow Peteski's advice about adjusting axle lengths, however. The Kato axles are 0.560" point-to-point, the LL axles were 0.532". The "somewhat" is it ran rough after conversion, you know, dirty-track rough. But the track was fine - all other 4-axle power ran great. It improved quite a bit after spritzing contact cleaner on the contact cones, which hinted at problems there. On checking the axles, they seemed to be too loose in the contact cones, so it's possibly a calculation error on my part shortening the axles too much, or they were loose to begin with because I didn't check for operation before the conversion. Either way, I need to take them apart and reposition the axles for better contact. Or maybe bend the contact strips to a slight curve in case I screwed them up in the handling.

Anyway, the Kato wheelsets work fine on the FA, just verify the modified axle length and contact condition.

SW8/9/900/1200 is another issue, unfortunately. I converted one truck, swapping the axle tubes. The centered gear on the switcher is because of reduction gearing in the truck. The problem is the Kato half-axles are loose in the LL tube. The Kato half-axles are 0.040", LL is, yup, 0.041". Damn those manufacturing tolerances! Adding insult, the LL axle tube does not set the gauge - you have to slide the half-axles for correct gauging. So the loose fit plus the gauging issue is going to result in reliability problems down the road. The axle fit is so loose you can knock it out of gauge simply by re-railing it.

It ran smoothly after converting the one truck, but that tells us nothing about possible contact issues similar to the FA if the axle lengths aren't right. I'm going to contemplate solutions for the axle looseness (Loctite? CA?), but will need to verify converted axle lengths first.

[reinhardtjh]

Life-Like SW's have a wheel set replacement at NWSL - part number 2675-6 according to this post on Trainboard: Atlas Code 55 track.  Damned if I can find it on the NWSL site though.  Haven't got the hang of their search engine. 

The post is from 2005 so it's possible NWSL doesn't carry them any more.