Lt Mtn 4-8-2 with a Wobble

[Scott_ATL]

I just received a brand new Lt Mtn 4-8-2 from TrainWorld. It's the DCC-Ready version, with the wire harness running to the tender so I can install a Digitrax decoder in it. Before I tackle that task, I wanted to run the loco for some break-in time, to make certain everything was ok. Right off the bat, the loco has a wobble, which is more noticeable on the straight-aways. I let it run for about 10 minutes, then noticed it was slipping on a 0% grade. Both traction tires had come off. I was able to get those back on, without disassembling the loco and after an hour or so, they haven't come back off. So, my question is to the wobble - is this something I can fix, or do I need to send it in? Honestly, I can live the wobble if needed, so long as it doesn't get worse - it's just frustrating.  It *looks* as though the #2 drivers are slightly out of true round....in ultra-slow mode, I can see a gap come and go between that set of drivers and the track as the train progresses down the track. All drivers appear to be "in quarter" as best I can see. And I really, really wanted a decent running 4-8-2. I know that if I send it in to Bachmann service, they have the right to replace it with another loco of their choosing. I do have another Lt Mtn 4-8-2 (a first run edition) that runs and pulls very well, but *hates* anything less than 17" radius curves - it'll jump my 11.25" and 12.5" radii in a flash. This newer one hasn't derailed once. I kinda wish I could merge the two locos. LOL

Tips? Advice?

[Bucksco]

Call the service department and ask for Rodney Watkins (215) 533-1600. Explain you situation and if he has the parts available he can fix (not replace) your locomotive.

[Scott_ATL]

Thank you!

[spookshow]

This sort of wobbling is usually caused by excessive freeplay in one or more of the driver bearing blocks (this due to the frame cutouts wherein the bearing blocks seat being slightly miscut). The simplest solution is to just send the locomotive back to Bachmann for repair/replacement. But failing that, one can often fix the problem by pulling out the offending bearing block(s) and shimming them (I generally use a small piece of electrical tape applied inside the cutout). Once shimmed, the bearing blocks are no longer free to move around and the eccentric rotation is eliminated.

Cheers,
-Mark

[Scott_ATL]

Thanks Mark! I thought Bachmann had that fixed with the new version of the Lt Mtn? Either way, the wobble seemed to get worse, so I've requested an RMA and am sending it back. I really hope they can fix it, as it has the DCC ready tender/harness and I wanted this loco to be my primary for my passenger line as well as my first decoder install. I have faith. 

[spookshow]

I think it's more of a QC issue than anything. Some have it, most don't.

Cheers,
-Mark

[gatrhumpy]

Keep in mind that when you fix this problem, you may be introducing another. I had a Heavy Mountain with the same problem. I shimmed it using a couple pieces of cut Scotch tape. Thought I fixed it. Then I discovered that I took out the freeplay in the drivers to negotiate tight-radius turns, and that killed it for me. I sent the thing back to Bachmann and they gave me a useless 2-10-2. Oh well.