Bachmann 2-6-6-2 1st run needs tuning

[nickelplate759]

I'd like some tuning advice.  I have a 1st-run Bachmann USRA 2-6-6-2.     It works pretty well, and pulls well enough for my purposes, but the #3 driver on the lead engine is clearly out of whack (has been since I got it).  It hops up and down once per revolution.   I'm pretty sure it's kinking the rail on my layout  .

I don't know a lot about tuning steam, but I know that a few folks that post here do.  I suspect this is an out-of-quarter issue, but would appreciate some advice on how to debug and repair this.

George

[victor miranda]

the better path is to ask b-mann, if they will exchange it.

if you want to tinker/tune I am sure help is possible.

are you comfortable with getting the loco apart and back together?

I need an evil grin emoticon.
You will get familiar with reassembly.

start with checking the quartering.
put one side cranks at the bottom.
turn the loco around, and all the cranks should be
even and at about 90 degrees from the bottom.

from here... things get complicated.

victor

[delamaize]

Victor speaks wisdom, Let Bachmann deal with it.

[Rasputen]

When I sent my first-run units back, Bachmann would only replace them with units from the second run.  They even made me ante up the price difference between the two    I would still recommend sending yours in.  There are too many issues with the first run units.

[mmagliaro]

The Jan/Feb 2010 NTrak Newsletter contains an article with photos I wrote on a whole slew of repairs
and improvements I made to a first-run 2-6-6-2.
Unfortunately, a slipped or out-of-quarter driver was not one of the things I had to repair
on that engine. 

But my point is, having been around the inside of that engine, I am really not a fan.  There are a lot
of troublesome design flaws in it.   If Bachmann will trade you
a second-run engine for it, it is probably worth doing, even with some price differential.   

[nickelplate759]

I'm getting back to this engine. How do you get the drive out of the shell?  The Bachmann instructions say "Put the locomotive upside down on your hand and holding the cabin firmly with your finger. (Beware not to hold the other parts of the body shell to tight) Meanwhile, use the other hand to pull out the chassis by holding the 'draw bar holding pin'.

There's clearly more to it than that - there's some latch somewhere that needs to be released.  Any pointers?

[peteski]

I'm getting back to this engine. How do you get the drive out of the shell?  The Bachmann instructions say "Put the locomotive upside down on your hand and holding the cabin firmly with your finger. (Beware not to hold the other parts of the body shell to tight) Meanwhile, use the other hand to pull out the chassis by holding the 'draw bar holding pin'.

There's clearly more to it than that - there's some latch somewhere that needs to be released.  Any pointers?

I don't own this model but it might just be a friction fit (like most of the N Scale diesel shells are attached to the chassis). Just speculating . . .

[mmagliaro]

I haven't had one here in ages, so I cannot remember how the engine trucks came out (or the rest of the mechanism for that matter).  Sorry.

[nickelplate759]

Don't need to take the trucks out, just get the shell off so I can get to the wiring for a decoder.  I can't get the shell off. Something is catching but I can't tell what.   I looked at the photo on Spookshow's site, but I don't see what could catch.

[Boilerman]

There was and may still be an article on the internet on how to install a decoder in these locos and if I remember correctly it tells how to get the shell off.

[nickelplate759]

Got it, finally - the problem was that the removable rear metal weight was out of position and the insulating plate that goes below it was jamming the shell.

[nickelplate759]

Next question - now that I've got DCC installed, I noticed that all the engine wheelsets are narrow in gauge (Doh!       Should have checked that first!)  What's the best way to safely widen the gauge of the drivers, and can I do it without removing them from the mechanism?  I'm always nervous about removing the drive rod pins and reinstalling everything correctly.

By the way - an odd note.   The screws that are used to mount the light board inside the smokebox (the actual light is on the pilot) cause a short to the frame when wired for DCC according to Bachmann's directions!   I had to remove them - ideally I'd replace them with plastic screws, but I don't have any handy.   Any idea what size they are?  I'm guessing something metric.

[badlandnp]

I widened the gauge on mine using a set of long pointed tweezers. Be sure they are strong ones. Slide them in between the back of the driver and the frame, gently with lots of light. Then pry the driver away a teeny bit. Do the same amount on both sides. If your eyes are sharp, you should be able to see the axle end suck into the driver a bit as you pry. Gently!

Good luck!

I added lead shot to every empty nook and cranny I could find on mine. That helped it pull some better. That and Bullfrog Snot on the tread of the geared driver, not that I remember which one that is.

[nickelplate759]

Thanks for the suggestion.   I wish I didn't want an NKP 2-6-6-2 so badly - I'd just sell it.  But, I do want it, so off we go!   All the wheels are narrow in gauge, not just the drivers.  I can re-gauge the rest of them easily enough.

[nickelplate759]

It's turning out to be harder than I expected (and yes, you all warned me...).  Even regauging the tender wheels isn't simple - they're .015" too narrow, but if I simply widen the gauge then the axle tips bind in the metal contact strips.  Similarly, if I widen the trailing truck gauge by 0.15" it will bind in the truck frame.  About the only axle that looks easy is the pilot truck.

Unfortunately, if I send it back to Bachmann, they won't replace it with another NKP 2-6-6-2, which were only made in the first run. 
So, somehow I'm going to try and make it work.

I've ordered a copy of Max's N-Trak article.