(Corrects ownership of bridge to Canadian Pacific not Union Pacific, paragraph 4)
The U.S. Coast Guard on Tuesday closed the Mississippi River at Sabula, Iowa, after a barge struck a railroad bridge, said Eric Washburn, bridge administrator for the agency's Eighth District Western Rivers Bridge Branch.
The river was closed 1 mile (1.6 km) north and 1 mile south of the site of the accident as of about 3 p.m. CDT (2000 GMT), Washburn said. The barge was stuck in an open position. The contents of the barge were unknown as investigators traveled to the site, he said.
"The investigators will have to inspect the bridge and make a determination if it needs repairs," added Tim Marriott, enforcement chief for the Coast Guard's upper Mississippi River sector.
The rail bridge was owned by Canadian Pacific Railway Ltd , said company spokesman Ed Greenberg.
The Mississippi River is the busiest U.S. waterway and the main route to ports along the U.S. Gulf Coast.
(Reporting by Michael Hirtzer in Chicago; editing by Andrew Hay)