Stub end passing side for the San Juan toward Durango

Another question(there are lots), regarding another scene in this film.
The photographer is riding the San Juan(remember this is 1949), and is stopped in a siding as an eastbound Doubleheaded freight passes with 481 and 484 and all box cars on the train. As the caboose passes we head out of the siding, and cameraman(must have been in the parlor car), looks back toward the caboose and you can see the end of the siding with no east switch, just a stub end siding on the south side of the mainline.
Anyone have any idea where this might have been? This is well after the San Juans had met, and likely west of Gato someplace judging by the scenery.
Greg Scholl