DM&IR began with the discovery of iron ore in N.E. Minnesota in the 1880's, assuming it's present name in 1937. DM&IR hauls millions of tons of taconite pellets annually over its 212 miles of track from the Missabe Range to Duluth and Two Harbors, MN.
The DM&IR was owned for many years by Great Lakes Transportation, owner of 2 other RR's and 8 ore boats. In May 2004 Canadian National purchased Great Lakes Transportation; it's not clear if CN will retain the DM&IR name.