The bridge, owned by Union Pacific Railroad, is not connected to tracks on either side. View Full Caption DNAinfo/Alex Nitkin

DOWNTOWN — The iconic railroad bridge just south of the Kinzie Street Bridge on the North Branch of the Chicago River that almost always is raised was lowered for several minutes this morning for its one truck crossing per year.

The bridge is lowered once a year so that a Hy-Rail truck (a type of pickup truck that can drive on tracks or roads) can go onto the tracks, which officially places the rail line in "active status," according to Union Pacific spokeswoman Calli Hite.

Never seen the iconic rail bridge south of Kinzie down. Workers checking it. pic.twitter.com/fXNgWqH6vK — Chris Fusco (@FuscoChris) November 19, 2015

The bridge, owned by Union Pacific Railroad, is not connected to tracks on either side and is almost always in the raised position.

Engineers also took the opportunity to install new lighting on the bridge, Hite said, to stay up to date with U.S. Coast Guard requirements.

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