Peco item #SL-300F N Scale Code 55 Flex Track box of 30.

Finescale is a unique product in that the rail is Code 80 in height, but 0.025" of it is 'buried' in the tie strip resulting in a track that appears to be Code 55. The benefit (besides a more scale appearance) is that this track is very strong since it does not depend on the molded-on spike heads to hold the rail to the tie strip. Also, the spike heads on the inside of the rail are molded in low relief allowing adequate clearance for wheel flanges on all but the most primitive equipment.