I have a good size three level 2 rail RR and an long eye level 3 rail recent addition just for the fun of it.
Same construction method, same environment, same wood, same Homosote.
In my world, Two rail is much quieter. Three rail is more forgiving.
(note: I must say I do run my three rail on the slow side. The sound was fun as a kid but at this stage life I find it unbearable to run at speed for more than a minute or so).
Some folks say; Two rail is more exacting. Three rail can be more fun.
If you ever get a chance to visit the Brandywine River Museum in Chester County PA during the Christmas season , you will get to see a approx. 30' X 75' siamesed combination 3 rail and 2 rail professionally built layout running all day long.
That visit may help you choose. I really like having both worlds in my man cave. I am in the process of doubling my three rail effort on a subterranean level. There is just something so nostalgic with 3 rail.
I say it is all good.
