It is not a break in issue.  Check your wheel gauge on all the wheels.  Is the tender hitting the engine on curves?  Which hole of the drawbar are you trying to use?  If you are going to run large steam locomotive models, you better get used to checking details and understanding everything about how they work.  Also, be advised that the bigger and better you go, the better your trackwork will need to be.

Everyone keeps saying "Factory Sealed" like it is some kind of holy grail or something.  I guess everyone does not realize that tons of people and places have the little machines so they can shrink wrap and seal ANY box, just like the factories do.  Until the factories start using some type of "watermarked" or logo embossed plastic, all sealed means anymore is that the box won't pop open if you drop it.

Just for clarification, I no longer believe Bachmann uses QSI decoders. 

After such a storage time you should always clean and lube engines.

Mike, I believe Spectrum uses QSI decoders, so all it ought to need is adjustment.
Jim, I understand what you are saying, but on my two cylindered locos the chuffs are close to perfect.  I do not know how, and hope I do not have to take apart the mechanisms anytime soon.  I did take apart one articulated to get the engines about 135 degrees out of synch, and the other came that way, therefore the furthest 'off' I can be is 22-1/2 degrees.  I have had two brass engines with sound and mechanical cams, and I don't notice a big difference.  Also, on some HO engines the wheels are not exactly at a perfect 90 degree quarter, so how good the timing was could vary depending on which side of the loco you were looking at.

Okay, I have to weigh in here.  I have 6 sound steam locos.  3 are articulated.  The two cylindered locos are synched at 4 chuffs per revolution and were that way from BLI.  And they are not close to 4 chuffs per rev, they are at 4 chuffs per rev.  Two simple articulateds slowly go in and out of synch between 4 and 8 chuff per rev at relatively low speed.  At higher speed who can tell?  They came that way from BLI.  The compound Mallet has been set to start in simple at 8 chuffs and switches to compound and 4 chuffs about 8 MPH.  It came set up compound from PCM and I changed it per the instructions.
I do not see how 2 chuffs per rev could sound better when that is wrong.
I am ALL DC, but I have a BLI box and a PCM box and I passed reading comprehension.

As noted, the numbered turnouts do not have a constant radius like the snap switches.  The number is the relative angle at the frog; on a #6 the route diverges 1" for every 6" of run, or approximately 9-1/2 degrees.  The rail to the frog curves, but is straight from the frog on the diverging route.
I also run rather large steam, and have never had an issue with #6 turnouts other than you do need to take them at a relatively sedate speed, and the dimensions better be in spec all the way.  For a crossover you plan to take at track speed, #8 does do better.  Some engines will not go thru a #4 turnout, so use them judiciously in yards, or select sidings only.
Good luck.

The relatively current  Spectrum 611, excursion version I got (and subsequently changed the headlight lens in) is gloss finish as well.  The stripe color is off a bit (not really news), but it runs very well.

I do not think Bachmann is in the business of doing conversions, OR that you would get the best results from having them do it, even if they would, which I doubt.  Check with Tony's or Litchfield is my advice.

Bachmann has also made Spectrum auxiliary tenders, in N&W, B&O, and Undecorated, and BLI also currently has Aux. tanks.  There are plenty of them on that auction site, and at tons of vendors.  They are all much more detailed than the '80s N&W Bachmann tank I posted that picture of.  It has been awhile since I looked at mine, but if I remember right that original Bachmann A tank, and the prototype it was based on, were both considerably larger than the original 1950s versions.  For my money (seven times actually) the Bachmann Spectrum tenders are one of the best deals going.  Trainworld did have them for like $19.  The brass ones used to fetch $140, but I haven't looked in a long time.

The best course of action would be to go on eBay and find one that looks EXACTLY like it.  Small differences mean a lot.  This locomotive has been produced several times, by several manufacturers, in differing era configurations.  Can't nail anything down without a lot more data.  Step one, look on the bottom for a name.

For picture purposes only
http://cgi.ebay.com/Norfolk-Western-RR-Steam-locomotive-WATER-TENDER_W0QQitemZ130089774352QQcategoryZ19132QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
This is the one that ran behind the J in 1982, and leaked all the way from Birmingham to Roanoke.

Good point Woody.  One of those L&M Big Emma tenders became the the black with a red stripe, and later all black excursion tender that ran behind N&W J 611 starting in 1982, and later behind N&W 1218.  The methodology Norfolk Southern used on that one was the same one N&W used back in steam days.  One of the same men oversaw the operation in Birmingham, if you watched the 611 rebuild video.
Ahhhh, memories of better days.

There is currently what is purported to be a model of a UP steam era aux. tender on ebay, in brass.  OMI if I remember right.  Different, I will give it that.
Most aux. tenders I have seen were all based on the N&W prototype; a regular tender with the fuel section removed and covered over so it was all water.  VGN aux. tenders were just like N&W's, but a little smaller as they had smaller tenders to start with.  To my knowledge PFM, Key, OMI, NWSL, Bachmann, and now BLI have all offered them over the years.

UP's tenders are pretty unique, and if I remember correctly, the ones they use in excursion service are ex-turbine unit fuel tanks.  I do not recall having seen an authentic UP steam era auxiliary water tender.
The Bachmann ones are generally patterned after N&W prototypes (and they just killed the brass aux. tender market).

I hate to tell you Sheldon, but Lima built the Allegheny, not Alco.  The Big Boy was Alco's heavyweight contender.  And as Lima's biggest, sadly it was a bit of an embarrassment after they got sued by the C&O over the weight, and it cost them something over $3 million to settle it.
I have always thought the VGN sort of messed up buying their 900s, much as C&O did with the originals.  Misapplication.  The only time they ever fell in that trap, but with ex-C&O management then on board why it happened is a no brainer.  That, and the smokebox air pumps, is another reason why I really welcome an excuse to live without one for another few years.  VGN should have bought N&W Class As.