On May 25, 1985, Soo Line tested Electro-Motive Division’s brand new SD60 demonstrators on a train south out of Shops yard at North Fond du Lac, Wisconsin. A train of 111 loads and four empties weighing in at 12,743 tons climbed Byron Hill without the assistance of the normal helper, powered by EMD 1 and EMD 4, along with Soo GP35 No. 727, GP38-2 No. 4401 and GP40 No. 734. They made it over the hill, and in this view are departing Byron, picking up a little speed with the Chicago-bound train. Soo Line was apparently impressed enough with the new locomotives to purchase them, with Nos. 6000 to 6062 arriving on the property between 1987 and 1989, with the last five being Soo’s only SD60M models.
