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Proto 2000 SW8/9 Chassis Warp / Zinc Pest

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  • Member since
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  • From: MN
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Proto 2000 SW8/9 Chassis Warp / Zinc Pest
Posted by Da Stumer on Saturday, September 17, 2022 5:16 PM

I just purchased a Proto 2000 SW8 off of eBay and pulled it out of the box to find that the frame was pretty significantly bowed. Kind of seems like a zinc pest issue. It's bad enough that the shell won't snap into place and the coupler boxes are angled low. I just initiated a refund request, but I also looked more carefully at the other listings to see how common it is. Quite a few SW8s and SW9s seem to have a tiny bit of warping, and I was able to find a couple more extreme examples as well. Have any of you encountered this and a potential fix?

The one I just received:

Other examples:

-Peter. Mantua collector, 3D printing enthusiast, Korail modeler.

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Posted by maxman on Saturday, September 17, 2022 7:32 PM

I thought that zinc pest related to a deterioration of the base metal. I'm not sure that frame warping has the same cause. 

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Posted by gmpullman on Saturday, September 17, 2022 8:18 PM

maxman
I'm not sure that frame warping has the same cause. 

I encountered quite a few Trix/Märklín U.S. freight cars with zinc pest that showed considerable warpage plus the associated brittleness.

 Trix2 by Edmund, on Flickr

The metal expanded to such a degree that it broke the styrene body shell from the excess pressure caused by the expansion.

 Trix5 by Edmund, on Flickr

 Trix3 by Edmund, on Flickr

Good Luck, Ed

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Posted by maxman on Saturday, September 17, 2022 10:58 PM

Thanks.  Learn something new every day.

Is it possible with zinc pest to have warpage w/o brittleness?

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Posted by csxns on Sunday, September 18, 2022 12:03 PM

I have a Intermountain ES44AC and notice the frame has bent.

Russell

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  • From: Vancouver Island, BC
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Posted by selector on Sunday, September 18, 2022 2:30 PM

I have one of those QSI-equipped SW-8 diesels, but I also have a Trix 2-8-2 and a GG1.  Last I knew, and the SW-8 and Mike were last used maybe two years ago now, neither seemed to have suffered any deterioration.  

HOWEVER....the GG1 is showing signs of what I assume is zinc-pest.  When I turn it over, the underside of the frame, even though painted or anodized, not sure which, shows splotches of what I'm guessing is bared/exfoliated metal.  Not bad, yet, but that's only what I can see. God knows what is happening inside the frame. 

This is most disappointing since the Mike and GG1 are in every respect very nice locomotives that track well, sound decent, and are rather fine looking.  One has to wonder how much feedback Trix/Marklin has received from disappointed customers who have gone on to state that they will no longer support the company.  I'm sure their loyal EU customers have begun to find the same thing by now, i.e., planned 'obsolesence'.

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  • From: MN
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Posted by Da Stumer on Sunday, September 18, 2022 5:40 PM

Thanks for the replies guys. What surprises me is how I can't find any mention on this issue with Proto SWs online at all, despite being able to find quite a few in pictures. I've read cases of Trix, Proto GP38-2s, and some Atlas locomotives, but not Proto SWs yet.

I bought the SW8 because there's a specific model I want to build, but this observation makes be wary of buying another. I'm thinking the solution is either to scratchbuild a new frame out of brass or 3D print one. I'm more comfortable with the printing option because I've never worked with sheet brass, and I find I'm very bad at making clean square cuts with styrene anyways. However, a printed frame will likely reduce weight on an already very light locomotive.

-Peter. Mantua collector, 3D printing enthusiast, Korail modeler.

  • Member since
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  • From: Vancouver Island, BC
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Posted by selector on Sunday, September 18, 2022 6:57 PM

Mine came with traction tires on one axle.  That was a hopeless bust across insulated frogs.  I contacted Walthers, the new owners of Life Like, and they sent me a plain axle free of charge. No problems after that. However, be warned that this a light locomotive that will have strictly limited potential on grades with strings of cars numbering than about two, or three. On an almost flat yard, it's a different story, and you can expect to move up to five Walthers or equivalent heavyweight pax cars, or perhaps eight to ten free-wheeling 40' boxcars. 

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Posted by hon30critter on Monday, September 19, 2022 10:59 AM

Da Stumer
I'm thinking the solution is either to scratchbuild a new frame out of brass or 3D print one. I'm more comfortable with the printing option because I've never worked with sheet brass, and I find I'm very bad at making clean square cuts with styrene anyways. However, a printed frame will likely reduce weight on an already very light locomotive.

Hi Peter,

I have built a few things out of brass, but no larger locomotive frames so far. Why can't your printed frame be designed so it can hold brass or lead weights? Or better still, why not start with a piece of heavier brass stock and 3D print the truck and engine mounts etc.

I have added a lot of weight to very small locomotives using 1/16" lead sheet available from roofing suppliers. Here are a couple of examples:

Click on 'Watch on Youtube' in the lower left hand corner to play the video:

Cheers!!

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

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  • From: MN
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Posted by Da Stumer on Monday, September 19, 2022 12:26 PM

Thanks Dave. I've thought about how to print a frame with weight integration, I'm just having a hard time picturing how I would make it fit. The stock weights that are screwed in place would be no problem, but finding room for weight in the frame while also finding room for structural supports seems like a challenge. I do like the idea of printing around a piece of brass stock though, that's something to consider.

Sheet lead is something I haven't really considered, but it might be what I need.

-Peter. Mantua collector, 3D printing enthusiast, Korail modeler.

  • Member since
    March 2016
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Posted by PRR8259 on Thursday, September 22, 2022 8:39 AM

maxman

Thanks.  Learn something new every day.

Is it possible with zinc pest to have warpage w/o brittleness?

No absolutely not.

Zinc pest is intergrannular corrosion.  It occurs throughout the metal piece and can eventually make the piece brittle enough such that it crumbles to dust in your hands.

This factually happens with old Lionel Train wheels made well prior to WW 2.  My old boss, Lewis K. English, Sr. who was a big time Lionel collector, saw it first hand on Lionel trains as well as other diecast toys from that period.

John

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  • From: Vancouver Island, BC
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Posted by selector on Thursday, September 22, 2022 5:07 PM

I just unboxed my SW-8 from 2006 with original QSI.  I moved the trucks back and forth and had a good look at the parts of the frame I can see.  I don't see any indication of zinc-pest. Whew!  Of course, it doesn't mean it isn't happening, just that I see no evidence of it...yet.

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Posted by Attuvian1 on Thursday, September 22, 2022 6:41 PM

Instead of waiting for it to appear, perhaps asking a followup question may help to expand the discussion: What other causes for this extent of chassis warping exist other than zinc pest?

I would think that alloys subject to pest would have been discarded well before the Proto locos came out.  I would also think that it has to be something that could occur during storage.  On the other hand, this might not be a materials issue at all.  It might have been bent mechanically.  And if that, a humpback like this one should be less likely than a swayback. Surely, what the OP has at hand didn't get past the QC folks.

This deserves more sleuthing . . .  

John

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Posted by Da Stumer on Friday, September 23, 2022 2:28 PM

The locomotive in the second picture I posted looks like it’s never been used, and my own seems to have very little use beyond the initial assembly. So either something must have happened at the factory, or some sort of reaction is happening.

There is precident for bad Proto 2000 frames though, as some E units and GP38s had zinc pest issues. I also found a post referencing a bent Proto SD45 frame that the owner attempted to straighten.

-Peter. Mantua collector, 3D printing enthusiast, Korail modeler.

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