Unless a car is being loaded or unloaded, you will  never see grain doors because the car doors are closed and sealed while the car is in transit. I see trains with open box car doors,  grain doors and loads on model railroads, but that’s not prototypical. It’s OK to have a car with open doors spotted by an elevator for loading or unloading, but not OK on moving cars except when an elevator car puller is in operation.

Grain doors were stenciled for return to the railroad owning them. I guess it’s OK to have a small stack of grain doors next to an elevator, feed mill, or freight house waiting to be returned.

Nelson Moyer