4′ x 8′ model train layouts is the most common size across HO scale and N scale. Majority of model railroads are constructed on a 4′ x 8′ layout. Also, it’s not too difficult to construct benchwork for a 4×8 model train layout.
If you are looking for a step-by-step tutorial on how to build a model train layout from start to finish including ideas about space saving layouts, multitude of track plans to get started and 7 bonuses on everything from benchwork, wiring to scenery. Take a look.