Thanks guys!  That's exactly what I needed. I've been all over the Bachmann site and could find none of this info.  So what labyrinth do I head down on the Bachmann site that gets me to the manuals as well as other technical info? 

Why is it so hard to find and download a manual for the Bachmann 44915 DCC decoder? Is it made by a different company? If so, what is their model number so I can cross reference.  A list of CV's would be nice. Or are they not programmable? Some kind of paper work or a note on where to find this info would be even nicer.  When I google "Bachmann 44915 Decoder Manual" I get some website that I have to subscribe to.   The Bachmann site doesn't have a section on manuals....does it? I'm not finding it there either. Isn't this the first thing a DCC enthusiast/customer would want to know?

The frame isn't designed in halves, it just one complete chassis. There's no drive belt either, just a worm gear, idle gear and drive gear config. The motor and idle gear are mounted on top of a single chassis assembly.

I've run it with progressing assembly: first the motor by itself (unmounted and then mounted with no load), then added the idle gear, then added only the geared wheel pair, and then added one pair of wheels at a time (with side rods) and then added main drive rods and then the peripheral valve gear rods........nothing sticks out.  But I think you are right, running it upside down relieves whatever is causing the noise. And the more rolling stock I add, the more pronounced it is.

If worse comes to worse, the the Bachmann parts catalog has the entire chassis assembly for $65.00 or just the lower portion (no motor or worm gear) for $25.00 or I guess I could just send it in for $45.00.  I was hoping there was some common issue that other people have encountered (and fixed). 

The noise started after running it for quite some time, however, I bought it used on ebay so the warranty won't cover it.

I pulled the weights out of my rolling stock on a recommendation from someone on this forum a few years ago.  If you do a good job laying track, they won't derail or wobble.  It worked for me after I re-laid my track.  I don't know how many cars you can do this with or if the curve radius matters.  I pull 7 cars with my 2-6-0 that came with the original Jingle bells set without adding weight to the loco.   Anyway, my simple Christmas track has min curve radius of 24" and max grade of ~4%.  I also clean and dry the rails regularly and I don't use the smoker....they gum everything up. Now the only thing that stops or derails it is the cat. Haven't figured that one out and I'm not allowed to squirt Tabasco sauce in the house.

For my bigger layout in the basement, I use the heavier locos and leave the weights in the rolling stock....and the cats aren't allowed in!

Good luck

Bill

My 2-10-2 Loco (Spectrum) makes a "thumping" noise as it moves on the tracks. It also seems to jerk or limp a little bit in rhythm to the thumping. None of my other Loco's do that so I know the track's OK.  I can't see anything that would explain the noise as it moves on the track.  It's hard to troubleshoot when I run it on it's back (in a repair rack) because the thumping disappears and the wheel movement appears smooth as far as I can tell. 

I've disassembled the drive gear and, to my untrained eye, I cannot find anything obvious. No apparent or uneven wear of axles or  axle journals.  All the linkage appears well aligned, lubricated, and moves smoothly without interference. i.e. nothing bent or hitting anything else.  Wheels pairs are parallel and properly spaced and the left and right side connecting pins are all offset correctly (relative to each other) and there's no slippage of wheels on axles. Drive and worm gears don't appear worn or damaged and are well lubed. And finally, the motor runs smoothly.

I understand it's a precision piece of machinery and, as such, beyond my skill set to completely analyze.  Another option for me is to replace the Drive Gear assembly. They're going for $25.00+shipping from the Bachmann parts store as opposed to $45.00+(who knows what) to send it in for repair.

So what am I missing?

Bill

Well folks, after careful consideration,  I just went out and bought a bigger, better, heavier loco.  I think I'll probably sell my 2-6-2 locos for parts on ebay.  The clip that i'm talking about is a spring metal wire about the thickness of a very thin human hair, curved into a "C" shape that's about 1/16 inch across.  The reason I was asking about them is that they are impossible to find if you drop one.  And I've dropped all I have. Even if I do find a source for them, I'd need to buy about a dozen just to get one installed.  I'm not that good with tweezers.

Well, lots of good ideas.  I followed my favorite one.  I bought a bigger, better, heavier engine.  Like the post said.....it was a good excuse to buy it.  My wife is skeptical.  Oh well.  Thanks for all the input.

So what's the secret to posting pictures?  I put together some diagrams to illustrate my dilemma but I'm not seeing anything on this page that allows my to paste, attach, import etc.  Whatever the "Additional Options" is meant for, it's not for posting pics or anything else that I can see. I've seen other posts with nice pics so I know it can be done.

later

Is there some underlying reason that some loco's have moved away from using rubber band-type traction drivers?  Even my little Bachmann 4-4-0 (with rebber traction) can pull quite a bit more than the 2-6-2 Prairie.  Ultimately, even my heavier (2-8-2) loco slips a bit....not as bad.  Having said that, I am in the process of lighting the weight on my rolling stock.  We'll see well that works.

later

Thanks to all for the replies.  The loco that gives me the most trouble is the Bachmann 2-6-2.  I'll give all the suggestions a try....and if no luck, I'll just run shorter trains and live with it.  I do have bigger locos: 2-8-2 and 4-6-2 that are more robust but I like to give them a rest once in a while. 

When I add more than 5 cars behind my 2-6-2, it slips and just sits there spinning or barely moves.  My track is level and a straight edge shows no dips or "wows." The cars are not excessively heavy and all the wheels spin freely.  I am very careful with lubricants on wheel bearings and motor/gear stuff.  I don't use liquid smoke on any of my locos.  I only clean the track with the erasure thingy.  I usually clean the drivers with track cleaner but I always try to wipe them dry (frantically!!!).  I've experimented with wheel spacing and I get nothing.  Are these things really that limited in pulling capacity, or is there something I'm missing? What do ya got for me?

later

Judging by the number of people "viewing" this note and the lack of responses, I'm thinking no one has an answer or no one knows what I'm talking about.

Oh well.

So where can I get some of these.  A while ago I bought a couple sets of 2-6-2 driver wheel assemblies, but they didn't come with the clips.  You know which ones I mean, right? Anyway,  I'm not seeing them in the parts catalog. The assemblies are useless without them.

Thank folks!  I'll try your suggestions.  I did buy it used so I don't know if it's assembled correctly.  I do tend to disassemble my "cheaper" loco's just to see what makes them tick, but I'm pretty conservative with the more expensive (or higher tech) ones.  I guess I'll have to get my hands dirty on this on and try to figure out the front triuck problem.  Thanks again.

later

My Bachmann Spectrum 2-10-2 HO scale Steam loco continually jumps the track on most of my layout curves. I used the 3' flexible track sections on cork bedding on plywood....nothing unusual there.  And I've checked the integrity, alignment, continuity etc of the track and nothing appears amiss. I haven't measured the curve radii, but they are all much larger than, say, the standard, non-flexible 22" curved track sections.  It's a big layout.

Here's what I've observed: I noticed that the valve gear cylinders interfere with the front truck wheels on the curves, forcing them to derail.  But even so, if I remove the front truck, there doesn't seem to be enough "side-to-side" play in the drivers to accommodate the curves and the drivers derail as well.  I also have an older Bachmann 4-10-4 that does not have problems with any of the curves. 

I tried prying the driver wheels out a bit to give them more play but they wont budge so I left them alone....don't want to force anything.  The front truck only goes on one way so you can't screw that up either.  I can't imagine that the 2-10-2 is so poorly designed for curves.  It's a real expensive piece of equipment.  I'm hoping mine is either mechanically defective or there's something simple that I'm missing. 

Is there some minimum curvature recommended for this model?  I haven't seen anything in what little literature I received with my Loco.  Anyone else run into this problem?