Years ago, pre-OGR Forum, a 2-rail modeler (Dave B) converted an MTH Burlington Northern center beam flat car to 2-rail. I always remembered that project as I had the identical car (don't even remember where/when I got it). Anyway, I stumbled across some nice lumber loads and decided that they'd be good for this car. Well, looking at the car, I realized that the old-style truck placement and excessive ride height weren't going to cut it. So I started cutting. I removed the ends from the chassis plate and cut out sections of the center sill to allow clearance for the new trucks (Weaver Roller Bearing with 33-inch Intermountain wheels. I made bolsters from strip wood. The contact cement is setting up so I'll drill the truck mounting holes tomorrow. Because of the added weight of the load, I removed the chassis weight. If this works out, I'll use the same technique on several MTH Autoracks I have.
The next step will be to figure out the correct height for the Kadees. Meanwhile, here are a couple of options I'm looking at for setting up the lumber loads. I'm leaning toward the second option, but I've seen them loaded all three ways.