Gents:
For those of you "stuck in the 50s" like I am, here is an interesting blog where steam era freight cars are discussed.
http://steamerafreightcars.blogspot.com/
As a preview, here is a photo from a blog post about weathering freight car decks which is a subject that appeared on the O scale / gauge boards in the past. The author is building a Pennsy F-22 flat car.
Since the author is modeling in HO, the Funaro and Camerlengo (F&C) model is a light car and did not meet NMRA recommended weight standards. The approach that the author used, wrapping a paper printed deck around a flat lead sheet in my opinion was a pretty inovative way to approach the issue.
Here is a photo of the completed deck on the resin frame.
This approach would work well in "N" scale too.
Another blog post has an article on making Rutland flat cars for marble service out of Athearn blue box kits. Since the author is a member of the NEB&W club, he labeled the flat cars per the club's practice.
A darn nice car for not a lot of money. This project carries over to multiple scales too. 
Regards,
Jerry
