This unit is the same as the EMD SD75M, with 4,300 horsepower (3,200 kW), HTCR radial trucks and a 72-foot-4-inch (22.05 m) frame. The only difference between the two models is the cab. The "I" in the model designation stands for "Isolated Cab". This type of cab is recognized by a seam separating the nose and cab components. This seam is a rubber lining that dampens vibration and cuts down on noise, because the cab is not attached directly to the frame on the unit. This was the last model that used the "I" designation in the model name; all further units had the isolated cab, but the model designation continued to use the "M". Buyers included Canadian National, the largest buyer with 175 units (now 173), Burlington Northern Santa Fe with 26, and Ontario Northland Railway with 6 (now 5).