The Intermountain Rock

[Kuchler10]

I just purchased a DCC/Sound SD40-2 from IM and it didn't run at all. SO I took the thing apart and did a few things to it including de-gunking the mechanism and gear towers and re-guaging the wheels. Not happy about it, but I get it. Now the mechanism runs fine, but only if I hold one side down. The mechanism is not balanced so it is not sitting on the track properly. The front right wheels OR the back left wheels are on the track. If I hold the trucks to the rails, everything works fine. Is there a fix for this sort of problem? I have seen and solved many different mechanism issues with diesels before, but this is a new one for me.

[craigolio1]

Sounds like a warped frame maybe. If it's brand new why mess with it? Get the LHS to go to bat for you or send it back to IM.

Craig

[JanesCustomTrain]

I know I am not a big help with your problem but I have a simple solution to avoid problems with Intermountain's pieces of ... (add what ever word you think fits), I simply do not buy them. I learned my lesson years ago, it seems THEY have learned nothing.

Jane

[Bendtracker1]

Just call or contact Intermountain about the issue.
They are a great company to deal with and will work with you.
Just be civil and explain the issue.


https://www.intermountain-railway.com/customerservice/customerservice.html

[Kuchler10]

I have found the culprit: I had the trucks in the wrong way, but only because that is the way that they came. I have two front trucks and no back trucks. This is because on the SD-40-2 there are wings on the trucks that are supposed to face towards the fuel tank. It now runs great without the shell, but is unusable with it on. I will get the correct part from IM. Thanks for the recommendations.

[wcfn100]

Can't you just turn that truck around?

Jason

[Kuchler10]

The problem is that the gearing on the trucks has to line up. The reason why it was rocking before was because the truck gears were on opposite sides. So in the picture below, the gearing side of the trucks is on the right side for both trucks, but the back truck cannot turn because of the side frame details. So if I flipped the back truck around, then the gearing would be on the left side, which is ok as long as the gearing for the front truck is also on the left side, but it is on the right. flipping the front truck would then result in the side frame details interfering with the truck's ability to turn. So it needs another side frame with the openings for the gearing to be on the opposite side so the wing details are facing the fuel tank. This is usually not an issue, because for most trucks, the detailing is symmetrical, so if a model is rocking, your truck gearing isn't lined up. But because the detailing is symmetrical, simply flipping the trucks solves the problem. This is not the case for the SD40-2.

[jagged ben]

The gearing does not have to line up.  I don't think that's why it was rocking.  To my knowledge these use the same trucks tooled by Atlas for the SD50/60, and there's only one part.

One culprit could be that one of the tiny plastic pins on the side of the truck towers that the mechanism rests on has broken.  That happens easily with these.  They are arguably the poorest truck tower design in N-scale. 

Did you take the trucks apart when you did your overhaul?  There are some quirks as to how they go back together, they look more symmetrical than they are.

[wcfn100]

One culprit could be that one of the little plastic pins on the side of the truck towers that the mechanism rests on has broken.

You can see in his pic the rear truck is the wrong direction.

Jason

[mu26aeh]

Yes, I've never heard of a front and rear truck.  Something else is causing this problem.  I just went down and checked mine, and short of taking them out of the frame, they are identical.  The gears are opposite to each other front and rear.  This is how they should appear, from a photo taken after I got mine last year.

20170109_173344 by Adam Henry, on Flickr

[peteski]

Another voice doubting front and rear trucks. The gears on the axles of both trucks do not have to be on the same side of the locomotive.  Actually, in most locos they are not (because they use the same truck for both sides).  Just like in Adam's photo in the post above mine.

[jpwisc]

I know I am not a big help with your problem but I have a simple solution to avoid problems with Intermountain's pieces of ... (add what ever word you think fits), I simply do not buy them. I learned my lesson years ago, it seems THEY have learned nothing.

Jane

You were right, that was no help at all.

[BCR751]

I know I am not a big help with your problem but I have a simple solution to avoid problems with Intermountain's pieces of ... (add what ever word you think fits), I simply do not buy them. I learned my lesson years ago, it seems THEY have learned nothing.

Jane

Absolutely !

[Kuchler10]

Ok I see the point about the trucks not having to be on the same side, but when they are, the mechanism ran fine, and when they aren't it wobbles and doesn't operate, so you can see why I thought that. I checked the truck tabs and nothing looks broken or out of place. I would say frame warp, but it works as long that one truck is reversed. I'll take it apart for the fourth time, put it back together and see what happens.

In terms of IM as a whole, their QC is questionable, but if you do work things out, they are fantastic-looking and operate well. I expected to have to do some work to get it to run well. What I didn't expect was to encounter a problem like this.

[peteski]

In terms of IM as a whole, their QC is questionable, but if you do work things out, they are fantastic-looking and operate well. I expected to have to do some work to get it to run well. What I didn't expect was to encounter a problem like this.

Well, the point is that you should not have to spend time to get a brand new model to run well.  Some people (like me) actually love to take models apart and see what is inside, and how to make them run better, but an average model railroader wants to just buy and run a new model. Many might not even have the skill or know-how of how to to disassemble the model and put it back together.  The QC should be better on most of the Chinese-made models. And less lubrication too!