I believe at one time Lionel offered a track planning kit using miniature scale track rubber stamps .
I couldn't find a picture on-line, but the item I am familiar with that sounds like this was not for doing full size layouts.
There were a bunch of these stamps in a small blue blue and white box (was maybe white track images on a blue background). This box was only a little larger than a deck of playing cards.
I think it had standard PW sizes for curves, crossings, straights, and O22 switches to match the O31 curves. Not sure if it had O72 track and switches or not (but I suspect maybe not).
These stamps were probably the size of the last segment of your finger, not too large at all. (I'm not going to guess at a fraction of 1:1 full size without having them in front of me )