Number 1050 is an Alco RF1A.  It was built in 1943 (builder #70661) for the U.S. Army, #8040.  The Alaska Railroad purchased it in 1947.  They retired and scrapped it in 1963.

Jack Klingbeil adds, "It is an Alaska Railroad photo. It is taken sometime before 1952 because the railbed is still in its old place. It was in 1952 when the railroad moved closer to the water on a new road bed. The Seward highway is currently on the old rail bed.  Also, the picture was taken approximately half a mile south of Rainbow."

 

Alaska Railroad photo from the Jack Klingbeil collection