I think this is the limit for a 4 x 8 layout. I have more than 169 feet of track in this layout. It’s all Kato Unitrack DC with three separate tracks. On each edge there are nine lanes with a working turnout. That’s a total of ten lanes on each side of the layout. A graphic and link to the layout are below.
Download the SCARM layout file here.
Ten Lanes for Three Tracks