054

It can depend on the maker, some use outer rail dia. some use center rail dia. maybe ties?

4.5ft +( tie/bed projection x 2, say 2½"each=5" for room for outside overhang in curves. .... might as well say 6" andt say 5ftX5ft table for a circle loop in a cardboard box

Peter Frenzel 010119 posted:

what is the minimum amount of feet required to handle a ful turn of 054 track 8 pieces?

Lionel and Gargraves are close to 54 1/2" circle and Atlas and Ross are 55 1/4" measuring outside rail to outside rail. MTH RealTrax and ScaleTrax are 55". 

Then, add clearance for engine and car overhang for your equipment - 2 1/2" - 3" is usually safe. Less is for your specific fitment needs and equipment.

I would use a 56" - 58" area. 

60" table top.   O54 outer loop. O45 inner loop. 

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