Photo courtesy of Trains Magazine, July 1948

Quoted from Trains Magazine, July 1948: "This consolidation, Alaska Railroad's No. 584, is used in mixed-train service between Anchorage and Sutton, and in freight service between Sutton and the bituminous coal mines of Eska and Jonesville"

Pat Durand's commentary: "My best guess is that this is #504 and the photographer could not read his own notes or the article did a misprint on the number. At the time these locomotives were numbered in the 501,2,4,5,6. range they had the traverse mounted compound air pump on the front pilot. In the earlier 400 number series they were mounted for and aft on the left side of the pilot deck. There never was a #584 on the railroad."

Added 3/27/23:

Patrick Durand - John,  By process of elimination, I think we have a photo of 501 former 401 taken prior to 1948 when the Harriman number boards were added. The hand rails, steps, cross mounted air pump, and even the holes in the bottom member of the pilot where the snow plow was removed for the summer all look dead on for the 501 roster shot. You already have this image in your roster identified as 584 by trains magazine and then corrected by me to 504 for lack of any other info at that time.   It could be any of the 400/500 class as they really were pretty much identical by 1946 to 1948.    As delivered some of them had the bell mounted on the brow over the headlight.

Dick Morris - I'm going to say a 400/500 class. If you blow it up you can see the outside journals on the lead truck which aren't typical of most lead trucks, ARR or otherwise. I don't know what the piping is on the right side of the smokebox, possibly the compressor governor, but The 400/500/ class has the same piping.

Time wise, it would have been after the Coffin feed water heater was removed but before Harriman number boards were added.

In notice something interesting when I was studying the 400/500 class photos. In all but one photo all of the 500 class had the compressors with the compressor cylinders side by side, centered on the deck. The 400 class had them front to rear, offset on the deck as on 557. The ARR apparently moved them at about the same time as the renumbering and when the Harriman number boards and the front mounted number plate were added.   I'm going to agree with Pat. In this photo of 504 the bell, headlight, and orientation of the compressor are all the same with another photo of 504.