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A precise box car model broken automatically

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A precise box car model broken automatically
Posted by BN7150 on Sunday, January 19, 2020 4:23 PM

Yesterday I bought a broken box car at a model shop. It was close to Kadee's PS-1 and cost only $3.00 including tax. Strangely enough, despite such massive damage, the roof walk and ladders were safe.


Disassembled and surprised. The floorboard made by die casting was cracked. It was so brittle that it cracked just by touching it with my finger. This is "zink pest." Perhaps the plastic roof's deformation has solidified due to creep over time. Do you know the manufacturer or the release year of this model? Has anyone experienced any repairs?

By the way, what is the English meaning of the word "pest", insect or disease?

Kuriu, Kotaro
Kyoto, JAPAN

 
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Posted by gmpullman on Sunday, January 19, 2020 4:36 PM

Hello, Kuriu

I'm quite familiar with these models. They are made by Märklin and marketed as "Trix" throughout the world.

 Trix1 by Edmund, on Flickr

When Marklin moved some of their operations to China it seems that there was a rather extensive run of "zink pest" affected models in 2005-2006. It also affected some very expensive locomotives.

 Trix2 by Edmund, on Flickr

Over the years I have bought quite a few of the Trix U.S. based cars and some are perfect, yet others suffer the fate as shown in your photo. In a few cases the zinc floor had expanded so much that it cracked the body at the door sills from the stress.

 Trix_MTH_PS1b by Edmund, on Flickr

In some cases the underframe can be easily swapped with one from a MTH brand box car. Others may work just as well but I happened to have several MTH cars and their body shell isn't very well detailed but their underframe was. I recall that I filed off the four mounting "nubs" and used a very small amount of Walthers Goo to secure the body to the floor but still be able to break the bond if necessary.

 Trix_MTH_PS1 by Edmund, on Flickr

If I retain the Trix underbody, which is vert nicely detailed, I normally remove the NEM coupler and swing bolster and make a filler piece out of .030" black styrene sheet then mount Kadee draft gear boxes using 0-72 screws and nuts. A small amount has to be filed off the end wall of the body to fit over the coupler box.

https://en.wikipedia.org/wiki/Zinc_pest

A Pest can be anything annoying or bothersome. Yes, an insect can be a pest but a neighbor or relative can be a pest as well Whistling

Good Luck, Ed

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Posted by SeeYou190 on Sunday, January 19, 2020 5:20 PM

If you have trouble locating a suitable underframe for it, Central Valley makes a 40 foot underframe kit that might work as well.

.

-Kevin

.

Wink Happily modeling my STRATTON & GILLETTE RAILROAD. A Class A line located in a personal fantasy world of semi-plausible nonsense on Tuesday, August 3rd, 1954.

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Posted by doctorwayne on Sunday, January 19, 2020 8:07 PM

SeeYou190
If you have trouble locating a suitable underframe for it, Central Valley makes a 40 foot underframe kit that might work as well.

While I've used the Central Valley underframe for their stock cars...

...and under these heavily modified Blue Box Athearn cars, too...

...they place the trucks very close to the ends of these cars.  That's not to suggest that it's unprototypical, but it reflects a fairly old practice, mostly from the '20s and earlier.
The Pennsy used a similar truck position under their X-29 boxcars (and possibly other car types, too) so it's not uncommon, but it is relatively outdated for boxcars.

Wayne

 

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Posted by Overmod on Sunday, January 19, 2020 8:31 PM

"Zinc pest" is from the disease sense (as in the English 'pestilence'): the problem appears as if due to a spreading malady.

What causes it is changes in temperature, not exposure to moisture or physical damage; it is not (at least not initially) a form of 'corrosion', but a phase change in the alloy of which the part is made, similar to the change in tin 'allotropes' between white and gray.

As such, there is no 'cure' other than to keep the part at a reasonably stable temperature; as I recall, it's allowing the part to become cold (as in an unheated attic) that starts the process going -- similar in a way to why enamel watch dials can crack over the years.

There is no real 'cure' other than by removing the phase-changed areas, putting the straightened parts in a jig of some kind, and casting material around them to bring back the part's dimensions.  Then keeping the repaired part at as constant a temperature as you can manage...

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Posted by gmpullman on Sunday, January 19, 2020 8:38 PM

I believe a bigger cause may be the alloy "recipe" used and the source or purity of those alloys. 

 

https://en.wikipedia.org/wiki/Zamak

A large problem with early zinc die casting materials was zinc pest, owing to impurities in the alloys.[3] Zamak avoided this by the use of 99.99% pure zinc metal, produced by New Jersey Zinc's use of a refluxer as part of the smelting process.

 

Some zinc alloy parts (pot metal) I've seen stored in awful conditions (an outdoor junkyard) look pristine after 30 years while others in climate controlled environments (air conditioned home) and carefully wrapped and stored look like dry Saltine crackers in a short time (4-5 years).

Regards, Ed

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Posted by dknelson on Sunday, January 19, 2020 8:50 PM

That's sad to see.  When those Trix cars were new they were noted to have some modest flaws in terms of prototype replication but were nice models and by no means inexpensive. 

THe phrase "Zinc pest" is fairly new.  I knew it as "zinc rot" and it (the phenomenon, not the term) was common even going back to some Lionel trains of the 1930s.  My initial trainset in HO was Penn Line and its trucks suffered from zinc rot.  So did many parts of the Varney F3 all metal diesel loco model. 

Dave Nelson 

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Posted by doctorwayne on Sunday, January 19, 2020 10:14 PM

This little brass Mogul, belonging to a friend, had a bad case of zinc pest in her driver centres (I first heard that term in the '50s, from my dad, and have always referred to it as such.  I suspect that for him, the term went back to at least the '30s).

It was so bad that the screws holding the siderods in place kept falling out, rendering it inoperable. 
That's the restored version in the photo, with all-new drivers from Greenway, a new can motor and a NWSL gearbox.  She runs better than she ever has.

I've also had early cast-metal truck sideframes and/or bolsters  pretty-much turn to dust, and have seen cast zinc boilers with enough zinc pest to make them unuseable.

Wayne

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Posted by BATMAN on Sunday, January 19, 2020 10:34 PM

I had a Kadee boxcar and one of the trucks just seem to disintegrate. Are trucks susceptible to this?

Brent

It's not the age honey, it's the mileage.

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Posted by mlehman on Sunday, January 19, 2020 10:53 PM

BATMAN
I had a Kadee boxcar and one of the trucks just seem to disintegrate. Are trucks susceptible to this?

If they're made of zinc alloy, yes.

I think that the Kadee trucks are something different - at least some of them. Their sideframes are listed as being either metal or HGC, what Kadee calls a "High Gravity Compound, weighs nearly the same as Metal Trucks but with more detai..."

Mike Lehman

Urbana, IL

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Posted by gmpullman on Sunday, January 19, 2020 11:01 PM

BATMAN
I had a Kadee boxcar and one of the trucks just seem to disintegrate. Are trucks susceptible to this?

I have a few very old Kadee couplers, some still in their kraft-paper envelopes, and they have definitely picked up a type of zinc corrosion. It may not affect the strength of the coupler but it does result in loss of finish and a pitting of the surface.

Admittedly, these were stored in damp basement conditions and these couplers are at least twenty years old.

If they arent too bad I brush them with a soft brass brush and apply a graphite solution to them and they seem OK. A few have decayed to the point of no return.

I've never had any signs of this on their trucks.

Regards, Ed

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Posted by BN7150 on Monday, January 20, 2020 5:22 AM

Thanks for all the comments. I will try the repair someday.

By the way, Japanese railroad modelers mistakenly remember zink pest as "season crack." The influence of a magazine. How about MR or RMC magazine?

In industry, it is called intercrystalline corrosion (intergranular corrosion?). According to the Osaka Prefectural Institute of Technology (pdf file), magnesium is added to prevent this. If the bullion was used many times, magnesium will escape. In addition, the quality assurance system of the Japan Die Casting Association started in 1961 inspects and certifies samples submitted to members every month. Kato seems to be a member.

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Posted by gmpullman on Monday, January 20, 2020 5:48 AM

Hello, again:

If you look closely at your photo you can see the monogram "TRIX" near the center sill of the car:

 Trix_imprint by Edmund, on Flickr

Kato die casting is superb Yes

Thank you and good luck,

     Ed

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Posted by fmilhaupt on Monday, January 20, 2020 6:24 AM

Speedwitch Media makes a resin replacement underframe for the Trix Union Pacific boxcars. While he made it specifically to match the welded underframe details of the UP's version of that car, other Trix 40-foot boxcars use the same body and frame, so it would fit those, too.

I've read that the underframe from an Accurail steel 40-foot boxcar kit can be made to fit with only some light sanding.

-Fritz Milhaupt, Publications Editor, Pere Marquette Historical Society, Inc.
http://www.pmhistsoc.org

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Posted by Medina1128 on Monday, January 20, 2020 9:18 AM

So, THAT'S what it's called. I was given some old Athearn passenger cars and the metal trucks had this chalky texture to it. I never bothered trying to fix those trucks. Especially ones that had split wheels (the wheels would be cracked from the axle holes out to the tread. I've never recalled seeing a thread on replacing wheelsets on those trucks either. The bolsters used some kind of swedging process to attach them to the sideframes. I still have some of those trucks, if anyone knows how to disassemble, and reassemble, them.

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Posted by csxns on Monday, January 20, 2020 10:16 AM

gmpullman
definitely picked up a type of zinc corrosion. It may not affect the strength of the coupler but it does result in loss of finish and a pitting of the surface. Admittedly, these were stored in damp basement conditions

I have some of the newer Kadee couplers #119 and other scale heads that have turned white but seem ok for now.

Russell

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Posted by BN7150 on Friday, January 31, 2020 5:13 AM


Thanks for your comments, the model has been repaired.


In the body shell, the rising frames of the side doorways were cut down by 0.4 mm.


The floor was made from a 1.5 mm thick styrene plate. The underframe was trimmed by 2 mm.


The brake piping and rigging were used as they were. The trucks were also used. The couplers were under-shank.

It is not perfect, but I think 90% have recovered. It's cheap because I enjoyed it for $ 3.00.

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Posted by NittanyLion on Friday, January 31, 2020 2:40 PM

Medina1128

So, THAT'S what it's called. I was given some old Athearn passenger cars and the metal trucks had this chalky texture to it. I never bothered trying to fix those trucks. Especially ones that had split wheels (the wheels would be cracked from the axle holes out to the tread. I've never recalled seeing a thread on replacing wheelsets on those trucks either. The bolsters used some kind of swedging process to attach them to the sideframes. I still have some of those trucks, if anyone knows how to disassemble, and reassemble, them.

 

That's a different thing called weissrot. It is a zinc corrosion too, but is mainly a surface corrosion rather than zinc pest being a problem in the crystalline structure of the metal. 

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