It depends on which code 55 rail you are talking about. On Peco or ME, it will run fine. But on Atlas, no.
It is also a matter of how fussy you are. Since they are only trailing and pilot trucks, some folks seem to run them
and not notice or care about the slight "buzz" on the Atlas code 55 ties. The drivers and tender wheels are okay, so
it pretty much does work on Atlas track.
As far as the "fix":
You can replace the pilot truck wheelset with a Fox Valley or some other 33". The trailing truck is still available as a part direct
from Kato at katousa.com - luckily. That is a larger diameter wheel, so when those run out, you'll have to hunt for some wheelset
in another steam loco that you can swap in there.
Personally, I have just removed the trailing truck wheelset, pressed one wheel off with a wheel puller, chucked the axle in a Dremel, and
turned down the flange with a diamond file. Then swap, chuck, and turn the other one.
It's not very hard to do. Make sure you dress it off with some 800 grit sandpaper
when you are done. It really does help the wheel glide more smoothly against the rails. A file leaves a pretty rough
surface, even if it doesn't look that way to your naked eye.
