What size rail will the RailRoller work with? May 10, 2019 19:23 Code 40 through code 148. Related articles What is the smallest radius that the Rail Roller can create? What is the Rail Roller used for? Can I use the Rail Roller with girder rail or bullhead rail? Is the RailRoller tool as awesome as it looks? I have a Fast Tracks assembly fixture for Micro Engineering code X rail. Can I use this same fixture for brand X rail?