To my way of thinking, cedar ties would be a very bad idea unless they are mixed in with other, harder ties. What is necessary is the hardest, most rot and insect-resistant wood available. While cedar may be rot and insect-resistant, it's almost as soft as pine, and we do not want to be plugging and respiking ties every few years. We need oak and mixed hardwoods, perhaps with a few yellow pine or cedar ties thrown in here and there -- but not on the curves.