Thanks, Catt.
I don't dispute that it could happen. There are a lot of "commodity" size trusses... 84 carries a stock of 4/12 24' trusses at just about every location, plus they have a pretty efficient regional rail re-load distribution set up, so there's a good chance that at some point they could ride the rails.
My only thought is that truss plants are everywhere, and no construction manager in his right mind would would pay for all that shipping to have something move so far and in such bulk that it needs rail transport. Trusses are primarily short haul, light weight, custom order type of loads, not something the railroads do very efficiently.
Lee