Not counting the loop around the Christmas Tree with my original Lionel Super "O" Set, I had two different layouts during the Postwar Era.
The first layout was a simple "oval loop" on a 5' x 9' table that my father built for me. Later, we added two Lionel remote control switch tracks that I received as birthday gifts.
The second layout was built on two, 5' x 9' tables. The tables were constructed in an "L" shape, also built by my father. I never expected to have such a large layout, but my father purchased the track for a very substantial discount in the early 1960's from a hardware store that no longer planned to carry model trains. I thoroughly enjoyed running the trains on this large layout by myself, and with my friends, for several years.