Inside the aging lock that is one breakdown away from crippling North America’s economy

SAULT STE. MARIE, MICH. – The dispatch tower above the Soo Locks on a fine July day offers a spectacular view, but there is little time to admire it. There are five telephones and five radios, and at 9 a.m. a radio squawks. “Go ahead, captain,” says Chris Albrough, lockmaster with the U.S. Army Corps of…