Maybe 6 wheel sprung passenger truck sideframes should be made out of stamped sheetmetal or a different metal than zinc?

SAME OLD SAD STORY - what else is new?  😐

I have seen the zinc pest problem on prewar Lionel die cast steam locomotives.  I have only seen it on trucks and couplers, and a couple of MTH die cast diesel frames for trains made in China.  Has anyone seen it on die cast steam locomotives made in China?

There's nothing wrong with die-cast...if done right.  Heck, they use it (and plastics) in making modern firearms!!!  If die-cast and plastic (done right) can take the beating from numerous 9mm rounds then a toy train ought to hold up fine.

The answer you're looking for is QUALITY CONTROL at the beginning of the process!!!

If the toy train lobby was as powerful as the gun buyers (nobody wants a gun that falls apart in their hands, no matter who made it) we wouldn't have these issues.  Of course, nobody's gonna point a Dreyfuss Hudson in your direction either

Pound on Lionel and MTH to fix this, MAKE them fix their lack of quality control!!!  Either that or just keep spending your hard earned $$$ on their inferior product.

I don't recall having any zinc-pest issues but I have less than 100 engines and rolling stock and none of my stuff is over 30 years old.

I would prefer brass or delrin myself.

When I brought up Zinc Pest/Rot in another thread I was told it was not a real problem. I lost the trucks on all of my K-Line HW passenger cars to it. 

So maybe we are just having a group bad dream. 

If you look at where these side frames fail, it seems to be in the thinner part of the castings, not the thicker top of the side frame. Perhaps they need to be stronger in the area that supports the bushing and wheel, as well as the spring suspension arms.

I suspect a bad casting would fail at the more delicate areas first. Stamped sheet metal would probably hold up better to the stress in those areas

Dennis LaGrua posted:

The answer of long lasting trucks is to cast them from aluminum. 

I think you might be right Dennis, if the thinner parts can take the stress of the weight of the car and handling.

It could be that the diecast is too brittle and the repeated handling (picking the car up  putting it down, bumping wheels on uneven track joints as the car is run), all might add to micro fractures in the casting that finally results in a broken sideframe, or suspension spring support arm.

That is probably the answer.  Tiny parts like that probably should be stamped steel.  But brass seems to hold up - I have maybe ten heavyweights with sprung brass trucks, and so far (30 years) no failures except for a couple of brake shoe electrical shorts.

AMCDave posted:

When I brought up Zinc Pest/Rot in another thread I was told it was not a real problem. I lost the trucks on all of my K-Line HW passenger cars to it. 

So maybe we are just having a group bad dream. 

I was told I was lucky I didn't have real problems like CA (which I suppose is true)   

Here is a photo of gorgeous trucks.  The one on the left is Sunset/GGD.  The one on the right is PSC.  Both have held up quite well.