Speakina' opinion, I chose Fastrack because (1)tie size and spacing is very close to prototypical and looks it and (2) Fastrack rail height is closer to prototype than Realtrax. Fastrack rail height is 0.190" (code 190) while Realtrax is 0.250 (code 250).
From an old discussion here (in which Bob gives his OK to use this image):
https://ogrforum.ogaugerr.com/...ack-andamp-real-trax
From another old discussion here, quoting member "CHUCK":
"PRR used 155# rail on their main line. This would scale out to code 172. For reference purposes, Atlas O two rail is code 148 meant to represent more typical and lighter weight mainline track in the 130# range. Branch line track could be even lighter while specialty tracks (like at a steel mill) could be even heavier."
