FECLionel, welcome to the hobby and the CTT Forum. I've been back in the hobby for 13-14 years after a hiatus of having Lionel's as a kid (starting before I was a week old). I've been repainting and restoring trains as long as I've been back in the hobby. Yes, I certainly encountered the attitude Elliot mentioned. But even years ago when prices were a little higher on the old stuff, I'd find things that I knew could be collectible, BUT certainly weren't in the condition I was buying them in.
Lionel trains became collectible because so many people had and played with them. The adults to some degree are buying back their childhoods. Pristine (postwar, prewar) pieces obviously will command the best prices - today and tomorrow. But there are so many other older trains out there that are far less than pristine. That coupled with the vast selection of new trains today with overall better paint and graphics and improved (opinions differ on this) operation. So I'd say do what makes YOU happy.
For starters, I'd do what you are already doing and mechanically get the engine running good. You obviously have some nostalgia for what the Lionel F3 is. You might just want to clean it up, touch up the pilot scratches and replace the nose decal. I'd consult with an expert on the Santa Fe F3 paint scheme... I've used Lemon Pledge to clean up old trains, as well as using Armor All to put a nice sheen on BUT different pieces respond differently to these things depending on the painting process. There is a company (they have advertised in CTT) that makes a product speciafically for cleaning older trains. CTT has also done some articles on this topic.
Somewhere down the track, should you decide to repaint it, fine. At least you'll be sure that's what you really wanted to do. I have no regrets on repaints and do them all myself. I love having my old favorite roadnames from the northeast U.S. (PC, LV, RDG, EL, CNJ, NH) but also love having new roads like CR, CSX, BNSF and NS: roads that have been underrepresented on new "traditionally" sized product. I love it when guys come over and say "but K-Line never made that in CSX" or "when did Lionel make the yard switcher in Norfolk Southern?" And my paint jobs stand up against any pro, so why not have the fun and do it myself.
That's what the trains should be about - having fun. For awhile there it was more about money. BUT it's the FUN part that helps determine true value, whether it be monetary or a priceless memory.
brianel, Agent 027