ARR #1605 is an Alco MRS-1 (verses the EMD MRS-1 like ARR #1718). It was built for the Army (#B2055) in 1953 was purchased by the ARR in November 1974 and retired/sold/scrapped in 1984. Originally designed to be used in Europe and the mid-east. They have variable gauge trucks and low clearance cab/hood to operate on foreign gauge rails and through the small European tunnels. ARR wound up with a batch of these and they were used in road freight and yard service.
Special thanks to Jeff Childs and Randy Thompson for the above information!
Photo courtsey of Charly's Slide Collection
(partial page taken from Johns Alaska Railroad page)