The Milwaukee Northwestern, is a "hug the wall" style that goes around 3 walls in my basement. Although it's not very wide in most places, it has about 2 scale miles of single track mainline and three yards. One of the yards is a diesel & car shop, complete with a roundhouse. All buildings and several cars and engines are scratch built. Most of the engines have been painted by me as well.
A three stall roundhouse in the Milwaukee Road diesel and car shop yard.
A switcher gets turned around on the small table.
A Milwaukee Road GP9 gets some service at the "Midtown" shop.
"Particle Board Inc", a business dedicated to making cheap furniture and pallets sits on the north end of the Chicago Northwestern yard.
A Milwaukee Road GP-13, a scratch built Geep made from sheet styrene.