Freight trains roll through the Chicago suburb of Barrington, Ill., every day, many pulling older tank cars known as DOT-111s. They're known as the "soda can" of rail cars, says village President Karen Darch, because their shells are so thin.
Many of the DOT-111s are full of heavy Canadian tar sands crude oil. Some carry ethanol. And more and more of them are loaded with light Bakken crude oil from North Dakota.