The C&NW bought five RSD4's (#'s 1515-1517 and 1619-1620) and ten RSD5's (#'s 1665-1677 and 1684-1690) from Alco. Of these, all the RSD4's and five RSD5's were equipped with steam generators for suburban passenger service, 1689 was so equipped as built. It appears to have acquired some sort of winterization hatch. This is probably this locomotive's retirement party.

I have a theory about those scuff marks in the dark paint below the Engineer's window. This locomotive is equipped with what was known as a "toe step", a piece of angle iron attached to the cab to allow maintenance people to walk from the cab door to the windshield by means of this step. Given the lack of grab irons between the cab door and front, I imagine a lot of maintenance people lost their footing and that's the marks of a men in trouble. The CB&Q had a similar arrangement on the Fireman's side, and also provided a grab iron mounted just below the cab window that ran the length of the toe step.