John, here are the photos to your heart's delight.  They had in the same file with them a letter saying "here are some photos" dated 1917, from AEC. However, since the M-107 is marked Alaska Railroad, these photos must be after mid of 1923 when the Secretary of Interior named it the ARR.    Who are the people?  Was it the congressional investigating commission? I do not know cars, but maybe some one else can date it that way.

The Fairbanks depot looks new, no grass growing around it.  No scratches in the paint.  Note, three rail track, I think. From foliage on trees the two pictures appear to be in the same general period, but at different times.  One can just see the "0" on the front of the M-107 in the people photo.  Note that in both photos the eight window is open, and the 3/4 view a person is hanging out of the M-107.  It's not muddy in either photo, so that with the trees and leaves, my guess is June, or late August.  However, I lean towards early June given the nature of the  leaves on the Balsam Popular trees.  I think the stripped down model T, is the same on the right side of both photos, but the second has the stakes in the flat bed. - Daniel Osborne