This bridge is in the process of being replaced. Last year the Moorhead portion of the trestle was replaced with steel and concrete trestle. The Fargo portion is being replaced this year and the main spans will most likely go after that. More information here: http://www.wday.com/event/article/id/86338/group/News/
The bridge here was actually done in four sections. Two Minnesota approaches in 2009 and 2010, then the ND approaches in 2011 and 2013. I doubt the girders are next. They aren't particularly old, and I believe they were strengthened not too long ago.