So far I am a little stumped as to the difference between all the turnouts. I will use either a layout that uses both 24" (048) diameter or 30" diameter (060) or one that goes with 18" (036) everywhere. Here are most of the numbers for items that look the same to me: 81949 048 turnout remote/command 12065 048 turnout remote 16830 048 turnout command control Remote? Command? Remote & Command? What's the difference? Also, the 048s come with little 12073 1-3/8" sections? Are these easements or to adjust clearance? Are they necessary? I'm building this suspended cieling layout probably with the combination 048 and 060 and on paper it looks find without the little joiners. . What do you think?