60% of grain exported from the USA goes down the Mississippi in barges. Usually barges are 3 wide and 5 long. They are pushed by a tug boat. They carry the equivalent of 870 semi trucks (approx. 35 miles of trucks at normal driving distances. They are huge. You can see the men on the deck in the front in some of the pictures. We had a train go right under us while standing there before they swung the train tracks and the bridge out so the barge tow could go through. Scared the daylights out of me. We couldn't see it but boy we could feel it.