There are some good plans in 101 Track Plans, and some bad ones. Don't expect to take any plan exactly. Also, N is 55% of HO, not 50% as the book says. Almost all plans in the book are standardized to 18", 24" or 30" curves in HO, which equate to 9.75", 13.25" and 16.5" in N. However, depending on equipment, there are good reasons for other radii. Many modellers in both HO and N use curves between conventional and broad. Equipment choices have also changed in 50 years. Far fewer modellers use "shorty" passenger cars anymore.