How can I tell if an N scale loco or rolling stock has low profile wheels that will work on Atlas C55 track? Is it obvious from looking at the wheel flanges? Or will I have to take my micrometer to the next train show? Are their certain manufacturers who make locos and rolling stock with low profile wheels? Atlas? Kato? Athearn?
You won’t need a micrometer, you will be able to tell just by looking at them. If the flanges resemble a pizza cutter, you’ve got the higher profile wheels. Micro trains makes low-profile wheels, and I’m sure others do as well. You can always replace the higher profile wheel with lower ones to accomodate your track. Rolling stock is much easier to do than locos, though.
Just about any new equipment is going to be compatible with Atlas c55. The only major exception would be Micro Trains, which continues to use flanges that are not only too big, but out of compliance with NMRA standard practices. That said, you can get replacement wheelsets from MT (and other vendors) to replace the so-called Pizza Cutters.
The only locomotives to be wary of would be anything released before about 1990, and some newer Life Like (pre-Walthers) diesels. These aren’t too bad, and you can easily grind them down a bit by putting one truck on a powered track, and a Dremel cutting wheel laid flat under the other, Reverse directions a few times, then turn the engine around to do the other truck. Keep a can of compressed air handy so you can blow any dust out of the gears.
Also, if you’re at a show, you can always ask the dealer if you can take the car out of the box and try it. Get yourself a 6" piece of sectional track to carry with you.