MTH-Coupler failure Degraded Metal

It is called Zincpest.

1. This is a known issue for several MTH cars and pops up from time to time.

2. You can replace the release armature lever.

3. MTH does sell the part, but I am not sure about the number (DD-13?).

4. Zincpest is a casting impurity, it can not be prevented from progressing.

5. The rest of the truck is usually good.

tplee.....this is a problem that has been talked about some time back.  There are other metal problems beginning to show up over time.  A fellow OGR member and I were talking last night and he has this problem on one of his locomotive frames!  The paint and metal are beginning to flake.  In my case, I have a MTH Bigboy that is showing this problem on one of the steam cylinders.  So....we may have a lurking problem that is starting to rear its head....??

Alan

Thanks very much for the replies.

Buzz

Yeah, had an MTH truck with this - different parts, same problem. Surprising in this

era. I do not think - oh, I hope that I am right - that this is a coming epidemic.

That would be really, really sad. Everything MTH turning to dust. Nothing left but

diesels. Ew. 

My K -line EP 5 had the truck assembly break apart. I can get a new part but it defeats the original bargain club price.

Not unique to MTH. I've seen it on all of the brands. The zinc used is an alloy and sometimes they get a bad batch. It just starts to disintegrate over time. Don't know if it's a moisture or dryness issue or a continuing chemical reaction as every piece I've had this occur with has been stored in its original box with the dessicant packs.

I know that they use zinc plates on bridges to prevent the load-bearing members from oxidizing. The zinc "sacrifices itself" in place of the steel. Maybe that's what's happening here -- not enough aluminum and/or magnesium in the mix.