I’ll be using Atlas Flextrack with manual switches. Is Code 55 the norm?
Don
No. Code 80 is the norm for N scale track. Code 55 is a relatively new product for N scale RTR track components. It’s a bit more delicate than code 80 track, is more expensive, isn’t as widely available, and has problems with cars and engines with big “pizxza cutter” flanges (which is most of the N scale equipment ever built).
As oronroy said there can be problems running with code 55 rail because of thr depth of flange on the wheels of a lot of N scale equipment. Micro engineering track is more forgiving than Atlas because the “spikes” are smaller.
The flanges on newer good quality locomotives (Atlas, Kato, MTL, Intermountain) (I’m not sure about LifeLike) should be ok. Newer good quality cars also have small enough flanges. Older cars and cheap cars can usually be easily converted with after market wheels or MTL trucks. Older locos are not as easily modified, requiring grinding and reshaping the wheel flanges.
Peco code 55 track looks smaller than code 80 but is actually a cleverly designed code 80 rail.