Taylor...
In the early 1970's we wanted to gussy up the C&TS RR boxcars that had been converted to passenger service, out of desperate need. We sanded them down to bare wood, to get rid of the flaked paint. It was horrible work for the peons involved, as the power grinder made great clouds of dust. See the Colorado Rail Annual No. 24, page 230, for a good look at the scarring that occurred from the sanding.
I was advised by a paint store salesman that modern products were far superior to linseed oil, but I went with it anyway. It just felt good to get something into the wood to take away the extreme dryness. I believe the paint jobs have held up fairly well, for some thirty years now.
An important thing to understand about "Rust-Oleum" is that, except for the primer, it is no different from any other paint. The primer, to the best of my knowledge and recollection, has ingredients that help it bond to rusted steel and iron surfaces, and form an excellent undercoat for paint, of whatever brand.
Bob Keller