Sweeping the box cars, Back in the day grain was shipped in box cars you could find empty's parked on a siding.
The cars were lined with planks and the grain would fill the gap, where there was a break in the planks the grain could be easily obtained.
Carrying Grain in Boxcars
The C&NW was shipping grain in 40' boxcars that leaked like sieves. Cars would come rolling down the hump smashing into cars in various and sundry tracks. Their resting spot would result in a trickle or stream of grain everywhere. Rain and sun would bake the surface of this "grain pie" crusty, while the inside was rendered gooey.