Layout

The minimum, without knowing your track system, would be 46" x 46" for a O-42 FasTrack layout to keep all the roadbed on the platform surface w/o overhang.

@ADCX Rob posted:

The minimum, without knowing your track system, would be 46" x 46" for a O-42 FasTrack layout to keep all the roadbed on the platform surface w/o overhang.

Do you have a drawing of what a 46x 46 would look like? Like a diagram

I just realized that FasTrack is not offered in O-42.

A 44" x 44" O-42 layout minimum would take up a 44" square area nominally, it would consist of a circle of 12 Lionel or K-Line O-42 20.17" radius curves.

Fastrack is offered in 31, 36, 48, 60, 72. I know a Fastrack Circle with 36 curves needs 40 inches on a layout not hanging over the edge so 48 would probably need 53 to 54 inches to not hang over the edge of a layout.

I should take a picture of my layout but I can do that later, how much would O-36 take in length?

Add four inches to the curve size to get min length layout board size.

0-36 + 4 inches = 40 inches

0-31 + 4 inches = 35 inches and so on..

Honestly, only you can decide how much space you want to devote to our hobby.  I grew up with O27(!), and we did okay with two 4x8's in an 'L' shape.  However, the total area devoted to trains was probably 14 x 10 because of "walk-around" space.  With today's wider curves, I would think of that as an absolute minimum.  If you're contemplating an "island" style layout wider than 6', remember that you might need to reach stuff in the middle!   Another thought: If you really want wide curves, you could stick with floor layouts for now, maybe you'll have a bigger room available to you in the future.  My $.02.

This is what my layout looks like, don’t mind the HO trains their gonna be out the way soon. If I were to expand the Lionel and try to make it O-31 how much room would I need?