Is the main goal to get as many tracks in as possible? If so you can get yard tracks as close as 1 3/4". When they are that close if one derails on a "center" track you can forget re-railing. Just have to take it out and put it on somewhere else.what center track spacing would you all recommend for a straight staging yard in HO scale Is not 3" standard?? ..., but I would not be doing any coupling Trying to get as many parallel tracks in a s possible.