Intermountain N scale F3A frame cracks

[Steve Smith]

@ peteski

Aside from very occasional running of the Intermountain F3's up to about five years ago, when not being run they and all my other loco's are stored in original jewel boxes inside a plastic tote, and kept in my layout room which is ground floor with 9" brick walls and a concrete slab for the ceiling.   

While it does get pretty hot in this neck of the woods (up to 115'F in summer), the layout room, while not air conditioned, is the coolest place in the house and my refuge during the summer months to get away from the heat.  Winters are pretty mild by your standards, maybe a low of 37'F, and no snow.

I think it is highly unlikely that heat is the cause in this case.

I sent a follow-on e-mail to Intermountain yesterday, so lets hope they respond.

Lets hope that this is a "relatively" isolated case and that those of you with F3's in your collections do not experience the same issue.

Steve

[peteski]

@ peteski

Aside from very occasional running of the Intermountain F3's up to about five years ago, when not being run they and all my other loco's are stored in original jewel boxes inside a plastic tote, and kept in my layout room which is ground floor with 9" brick walls and a concrete slab for the ceiling.   

While it does get pretty hot in this neck of the woods (up to 115'F in summer), the layout room, while not air conditioned, is the coolest place in the house and my refuge during the summer months to get away from the heat.  Winters are pretty mild by your standards, maybe a low of 37'F, and no snow.

I think it is highly unlikely that heat is the cause in this case.

I sent a follow-on e-mail to Intermountain yesterday, so lets hope they respond.

Lets hope that this is a "relatively" isolated case and that those of you with F3's in your collections do not experience the same issue.

Steve

I was thinking more of the moisture (humidity) than heat as the possible cause of the deterioration.  Where I live, we have hot and humid Summers,but not quite as hot as what you have, however the humidity makes the heat more unbearable.

I agree that what you are seeing here is probably not frequent occurrence, or we would be hearing lots of modelers mentioning the problem.  I wonder if the problem is isolated to a specific batch of metal rather than the entire production run.

My FT set is stored in my basement workshop. It never gets above 80 degrees or below 55 or so.  I have a portable AC and a dehumidifier runnign in the humid Summer months, so it never gets very damp there.  I hope that my FTs are ok.

[rrjim1]

I just checked my 6 IM F7s and they all look OK.   

[randgust]

Agreed, worst case of zinc rot I've ever seen.

I think the old Atlas/RR failure rate over time was about 50%, I've got, um, three 4-6-2's literally in pieces now with cracked frames, and one Atlas FM frame that was split since day one when I had no idea what 'zinc pest' even was.

Controlling metallurgical quality in many things China is still an issue, not sure why, but every time a screw snaps in half or the head snaps off I'm checking the box.  Yup.  The designs aren't necessarily bad, but the material consistency and certification is still decades behind Japan, and it's not just trains.   They can do it, they make hi-tech stuff, but your run-of-the mill production for metals is still all over in terms of quality.

This is disturbing though and I'll have to check mine.   I'm inclined to believe an individual batch of bad material rather than a substandard spec.  But didn't Atlas and IM have the same Chinese factory or is the design similarity more coincidence?  I may bust on them because they are too light, but I've never seen any Atlas China frame go bad.

[thomasjmdavis]

I've checked the 9 I have, everything looks OK for the time being.

This has been a surprise.  I've never had (or don't remember?) a mechanical problem with an IM unit (granted, haven't run them much).  I don't think I've had a "zinc rot" type problem since my HO days 50 years ago.

[tehachapifan]

Had one tunnel motor out of about a half dozen do this and IM replaced the frame for me. I inspect the others periodically and, so far, no additional issues found.

[Steve Smith]

@ Peteski - we do not experience excessively high humidity levels.   We have a Mediterranean type climate (similar to California), and humidity levels are relatively stable throughout the year, ranging from 60% in Summer to 80% in Winter.   

I can only surmise that there was a bad batch of zinc used for the frames, and that would imply that there are more duds out there waiting to be discovered.

Steve

[Caddy58]

I have exactly the same issue on IM F3.
Frame cracking and expanding to the point where the shell breaks at the end. Frame disintegrates and crumbles. 
Typical early warning sign is the mechanism starting to bind: engine develops a squeal and runs slower.

No issue ever on FTs or F7.

First instance was a few years ago with 3 frames cracking. In one engine only one half of the frame cracked and expanded, which curved the engine.
Contacted IM with pictures; they did send me replacement parts (no cost for me).

Since then 2 more engines failed; I have replaced the mechanism with F7 mechs.

Cheers
Dirk

[Cajonpassfan]

Ouch, but this is odd...the F3’s crack and the F7’s don’t? Aren’t they the same mechanism?
Perhaps a particular run of F3’s that went bad due to a defective alloy or exposure?
I have a whole bunch of IM FT’s, F3’s and F7’s, thirty plus, and never noticed a problem, but mostly they live in boxes as I’m working on the layout. This makes me nervous...
Otto K.

[nkalanaga]

Not really helpful if you have an affected item, but maybe of interest to younger readers, since zinc pest is rare today.

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

From the article, humidity "above 65%" increases the rate of the reaction.

[peteski]

Not really helpful if you have an affected item, but maybe of interest to younger readers, since zinc pest is rare today.

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

From the article, humidity "above 65%" increases the rate of the reaction.

That is exactly why I mentioned humid climate as a possible cause.

[Englewood]

Hopefully this doesn't happen to their Cab Forwards. I've never heard it, thankfully.
I used to collect Hot Wheels and zinc rot would sometimes affect the cars, so it's not just a model railroading thing.

[SkipGear]

Just a note, the new F unit's, when and if they arrive from IM will have a different frame as these will be updated for sound decoders. I think that is one of the reasons it is taking so long for them to arrive.

IM used to produce a metric crap ton of mechanisms and have them stock piled so a new run of loco's, just needed shells to be produced and painted. I've called looking for a specific loco before and they always reference making sure they have the shell and a frame to mate up to send it to me. They mate them up as needed.

[peteski]

Hopefully this doesn't happen to their Cab Forwards. I've never heard it, thankfully.
I used to collect Hot Wheels and zinc rot would sometimes affect the cars, so it's not just a model railroading thing.

The Zinc Pest problem can (and does) affect any item made from that alloy.  I even have a Miller Beer animated neon bar sign were its internal frame is made of white metal and it is also deteriorated due to the Zinc Pest.  Thankfully the distortion is not severe enough to affect its functionality, but I'm not sure how stable it is.

[rschaffter]

I have an ancient set of IM FTs and they appear to be fine...