Boxcar market "value"

Defer thinking about "cost-to-purchase" as-is.
Plan out everything else, in real detail. Have it audited by at least two friends and a very neutral party - all who have been-there and done-that. Restoration may cost a lot more than "cost-to-purchase" and also take several years of your life. How many years do you have available?
And what are you or your heirs going to do with it?
Especially if not complete.
Join us next June or August in Chama/Antonito. Most cars are consuming gangs for years.
Nearly every railroad museum has a deadline out-back and out-of-site that they may or may not admit that they will never get around to.