I will most likely model some special "Grain Handling" boxcars for my layout by adding two roof hatches to Plug Door Box Cars .( I've seen photos of the prototypes) I am interested in learning about the earlier methods of utilizing box cars for grain shippment. Temporary grain doors (planks stacked on edge with grain sack "caulk" !?) Paper Grain doors (Cardboard liners to eliminate the grain sacks ???) How were these cars loaded-unloaded, etc etc. Any light shed on this subject would be appreciated.