Old MTH Railking Diecast Fatiuge

Likely one of the famed cases of internal metallurgical breakdown.  This issue goes way back in the history of model trains, but some MTH products from the 90's (I believe) have exhibited the same problem.  I have heard of this happening in some trucks on MTH Amtrak passenger cars from this era, too.  Perhaps others with better specifics can chip in on this.

Contact Midge in parts at MTH on Monday.  I believe we still have chassis for that locomotive.

zinc pests!!.....every once in a while there are reported cases on the forum, usually its attributed to impurities in a particular batch of casting material. dampness and constant humidity can accelerate the condition. If you are concerned about humidity in your train room, check it out with a meter. I lost one frame on an early MTH 080 to zinc pests.....the little *******s didn't eat the wheels!

Jon G .......think ya'll might have railking 080 chassis hanging around? .......sorry Allan, didn't mean to hijack your thread!

I've reported on the metallurgical science behind "zinc pest" or "Dorfan's disease" in past threads. Bottom line, I expect to see this issue presenting in more and more trains made by Asian contractors starting in the 90's. I've sold off most of my trains from this era because of this very issue. Obtaining basic materials from suppliers that meet ISO and ANSI requirements in Asia is a gamble since QC is spotty or nonexistent. We don't see this in our Postwar/MPC/Fundimensions/LTI (US Made) as most suppliers of Zamac billets had excellent internal QC programs. 

We've also seen issues with poor plastics too. Many have reported issues with large O scale diesels and rolling stock where the shells were distorting from plastic memory and breaking away from the frames.

Definitely zinc pest. Unfortunately, you cannot stop it once it shows on a piece. The only option is to replace the affected pieces. Is it the frame or just the wheels? I would inspect all the wheels as well as any other castings on the engine.

Chris

LVHR

MTH has replaced some of these under warranty, even though they're pretty old.  I know that Harry at Henning's got a torpedo shell for a tender that developed swayback from them, and it was pretty old.

harmonyards posted:

Jon G .......think ya'll might have railking 080 chassis hanging around? .......sorry Allan, didn't mean to hijack your thread!

I'll need an item number.  Can check on Monday.

check this old number out Jon!.....its from back in the day!.....RK-1111LP N&W 0-8-0 thanks for checking!

While cleaning my layout for tours coming up and was cleaning shelves and found an older K-Line Western Pacific Blue Feather boxcar and one of the trucks had completely failed due to zinc pest. I found this out as a took the boxcar out of the box and the one truck, in many separate pieces, followed along. Thankfully I had a spare truck left over from another project. K-Line from the early to mid 90's seems to have this same zinc pest issue.

Jon G posted:

Contact Midge in parts at MTH on Monday.  I believe we still have chassis for that locomotive.

I checked with Midge and their are no chassis for that locomotive.  It is common for MTH to use the same chassis for other locomotives, so I did find a chassis for a streamlined Hudson.  You will have to compare photos to see if they are the same.  Part numbers are DF-1200026 with gray spoked wheels and DF-1200069 with black Baldwin disc wheels.  Chassis is 9-1/4" long.  I will have to measure driver diameter and spacing if the chassis look the same.  However, there is a possible problem like we had with the Hiawatha chassis.  The PS1 and PS2/3 are different.  Mounting the socket in the cab is not a bolt-in, threads are metric instead of SAE for mounts and the gear ratio was different necessitating a new motor. So, it may not be that simple...

harmonyards posted:

check this old number out Jon!.....its from back in the day!.....RK-1111LP N&W 0-8-0 thanks for checking!

The chassis for that switcher is DF-1200007, but I did not see any in the parts room.  There may be a PS2 version, but it may have the same problem as discussed above.

thanks for looking Jon!....If I call Midge, will she be able to tell me if the chassis interchanges?....Id hate to get rid of the loco or shelf it, my dad gave it to  me, so Id like to get it fixed, If I have to buy a chassis and a motor Id go that route....

Allan, I hope you don't mind me coat-tailing your thread....

harmonyards posted:

thanks for looking Jon!....If I call Midge, will she be able to tell me if the chassis interchanges?....Id hate to get rid of the loco or shelf it, my dad gave it to  me, so Id like to get it fixed, If I have to buy a chassis and a motor Id go that route....

No, she will not know.  The best we can do is photograph a chassis, if one is available in PS2, and you will have to compare the dimensions, mounting hole locations, etc., to see if it's compatible.  I doubt we have one in the archives to compare.

So how common is zinc pest in mth products? I read these threads, worry, check my stuff and everything inhave so far is ok. My oldest mth railking are an nw 0-8-0 and prr k-4 1361 with ps1. Both still look and run like new. Is zinc pest just going to rear its head if i keep them long enough or is it totally random based on the day or batch when they were cast?

Is the loco in question made in Korea or China?

country of origin will be on the box

I'm trying to determine which country's production is having these zinc pest issues

You might consider looking around for an old locomotive on places like eBay and stealing the chassis for your repair.  I've gone that route a couple of times.

Dave Funk posted:

Is the loco in question made in Korea or China?

country of origin will be on the box

I'm trying to determine which country's production is having these zinc pest issues

I've observed casting issues from both Korea and China. The occurrences are spotty at best and seem to be affecting products made before 2000. I might add that poor castings can also be caused by failure to maintain the Zamak at the proper temperatures during the casting process. In other words,failures many not be material related,but process related. I personally lean toward this root cause as precision die casting was new to the Asian train contractors during this period. 

Zinc-pest was coined by the Marklin collectors back in the 60's. In early postwar (1946-48) Germany there was a shortage of good casting materials, Maerklin made HO trains with just about any material they could obtain.I've heard of old tire weights and toothpaste tubes being melted down. A good part of this early HO production just warped and crumbled and turned to grey dust. 

Jon G posted:

Jon G posted:

Contact Midge in parts at MTH on Monday.  I believe we still have chassis for that locomotive.

I checked with Midge and their are no chassis for that locomotive.  It is common for MTH to use the same chassis for other locomotives, so I did find a chassis for a streamlined Hudson.  You will have to compare photos to see if they are the same.  Part numbers are DF-1200026 with gray spoked wheels and DF-1200069 with black Baldwin disc wheels.  Chassis is 9-1/4" long.  I will have to measure driver diameter and spacing if the chassis look the same.  However, there is a possible problem like we had with the Hiawatha chassis.  The PS1 and PS2/3 are different.  Mounting the socket in the cab is not a bolt-in, threads are metric instead of SAE for mounts and the gear ratio was different necessitating a new motor. So, it may not be that simple...

DF-1200026 grey spoked,

DF-1200069 black baldwin discs

Jon, thanks so much for contacting midge. I sent her an email a few days ago with a reply. Not sure if shes away, or my emails are not going through. Hate to bother her re-emailing her on small stuff, she is a busy person there!  Jon, As for the chasis, i re-listed above, do you have them? Or its at MTH? I know they ask for an exchange. Do you know the prices? Even if the chasis is different. The engine is and old Proto 1, with only a whistle, It doesnt have to match, and i can drill/tap threads if the chasis fits. As long as it runs, the owner is happy. 

I have done this swap before and the chassis will work.  Many of the PS-1 used similar design.  Wheels design are the issue.  I used the DF-1200026 to replace a MWR DF-1200020.  I reported this as an option to MTH.  I have also pulled and replaced bad wheels when that is the only issue. 

I can do this for you if you need a tech.  E-mail is in profile. G

Allan Loczy posted:

Jon G posted:

 

 

Jon, thanks so much for contacting midge. I sent her an email a few days ago with a reply. Not sure if shes away, or my emails are not going through. Hate to bother her re-emailing her on small stuff, she is a busy person there!  Jon, As for the chasis, i re-listed above, do you have them? Or its at MTH? I know they ask for an exchange. Do you know the prices? Even if the chasis is different. The engine is and old Proto 1, with only a whistle, It doesnt have to match, and i can drill/tap threads if the chasis fits. As long as it runs, the owner is happy. 

Midge was out most of last week and should be back mid week.  MTH has the frames. You could enter the part number on the parts order website to get a price.

I looked up the parts via the website, no luck, no results

Normally, MTH requires and exchange on chassis.  So you need a tech to do this for you, unless Midge is willing to sell and have you send in the chassis.  G