I received these photos from Charlie Drum's son. He is moving to France and found them while cleaning. I wondered if they were Alaska Railroad photos, so I consulted historical expert and ex-Alaska Railroad employee Rick Leggett. He replied,

"Definitely ARR and looking at metal hardhats, maybe early 70's. I don't remember ever seeing this one, but it is the bridge we filled in just north of our MP-350 line change in the early 80's. It is definitely the bridge we filled in at MP-350, because one of the photos shows an outfit car on the stub track at "Cascade." Don't know the year for sure, but I'll still guess the 70's."