Background: A good friend is recovering (well, still surviving) from treatments for throat cancer. They perdominately heat with firewood. A sawmill in the general area has a large pile of railroad tie ends from freshly cut perdominately oak. Tie ends would make good firewood for them once split. I have a Dodge D350 duelly flatbed with a, I believe, 360 gas engine. Since the tie ends can be stacked very tightly I'm wondering what would be the maximum safe weight to carry expresessed in terms of cubic feet. Truck bed is roughly 6' x 9'. I'm guessing around 45 pounds per cubic foot.