Cursory search yields two things: Flour mills [0] and railway system [1] [0] https://www.mnhs.org/millcity/learn/history/flour-milling https://www.mnhs.org/mil

Cursory search yields two things: Flour mills [0] and railway system [1] [0] https://www.mnhs.org/millcity/learn/history/flour-milling https://www.mnhs.org/millcity/learn/history/flour-milling [1] https://en.wikipedia.org/wiki/Great_Northern_Railway_(U.S https://en.wikipedia.org/wiki/Great_Northern_Railway_(U.S.)