The Dan Patch Line bridge across the Minnesota River will swing shut to carry rail traffic this spring for the first time in nearly a decade, officials said last week, and it’s being set in motion by an unlikely source: the Panama Canal.

A long-awaited project to widen the canal is scheduled to be completed in May, allowing larger ships to pass through the historic link between the Atlantic and Pacific oceans.

“That means bigger ships will be calling at New Orleans,” said Mark Wegner, president of the Twin Cities & Western Railroad Co., which owns the bridge. “That means New Orleans will be more competitive. And that means the [Mississippi] river will be more competitive.”

Wegner said he believes barge traffic from the Minnesota River port of Savage will be on the rise this year. The port is being affected by far-flung economic forces, he explained.

A worldwide glut of iron ore has lowered prices and idled ore fleets, and Wegner expects those ships to stay busy by hauling grain.

There’s a lot of grain to haul. Low prices last fall persuaded many farmers to keep their corn, wheat and soybeans in storage.

“Probably 70 percent of last year’s harvest is sitting in a country elevator or on the farms,” Wegner said.

Rail traffic on the bridge won’t be high, probably about one train a day, Wegner said. But they will be the first trains on the bridge since 2007.

And the Twin Cities & Western has been taking pains to let communities along the track know that its trains will be hauling grain.

“I want to make sure the residents know that we are not shipping crude oil,” Wegner said.

Minor repair work on the bridge started after Thanksgiving and will be completed in time for the expected opening of service.

The bridge once carried cars as well as trains, but that ended more than 30 years ago. A recent proposal by Scott County to reopen the bridge to auto traffic has been vigorously opposed by the city of Bloomington.

In the last decade, legislators shot down the idea of using the Dan Patch corridor for a commuter train from Northfield to Minneapolis, although some cities along the route still hold out hope for train service someday.