Bachmann Spectrum HO Norfolk and Western J Class 4-8-4 locomotive

[TomCuneo]

I purchased a new HO J-class 611 on ebay that was still in the sealed original box.  I opened it up last night and decided to run it.  The DCC works great but the engine constantly falls off the track.

I have a couple of questions.  Is the 0AC01 / H82103 wheel set attached to the locomotive with just a SINGLE screw?  Those wheels are  just bouncing on the track.  Is there something I need to adjust?

FYI, I purchased this N&W 611 because I was lucky enough to actually take a ride on the original this summer.  It was truly amazing and I had to find a Bachmann HO version!