Barge Going Through Lock and Dam No. 10

This picture was taken in Guttenberg, Iowa on the Mississippi River. It took an hour and a half for this Barge to pass through the Lock.
There are 29 of these Locks up and down the River. The Locks are to maintain the nine (9) feet depth required for the Barges to navigate on the River.
Notice how close the cars are to the sides of the Lock. The cars are 105 feet wide and the Lock is 110 feet wide.