ARR #1611 is an Alco MRS-1. It was built for the Army (#80391/31630) in 1953 was purchased by the ARR in 1975 and retired/sold/scrapped in 1983.   In total 13 Alco units were transferred to the Alaska RR. The photo was taken in 1983 at the north end of the Anchorage roundhouse, track 3.
 

Photo courtesy of Bob Yost