Courtesy of the University of Idaho.
See what this location looks like today.
Looks like the GN mainline has just been restored, and that likely was rerouted around the specific site where the siphon would cross by building a temporary track a bit further south. Looks like that temporary track was recently removed and the original line was replaced.
Note the body of water on the left. That is Crab Creek. Part of the Adrian Irrigation Company ditch was removed for the digging of this project. Waters from Crab Creek were diverted into a ditch that ran through here all the way past Adrian for use to the west of town. Parts of the ditch can still be seen in the aerial view linked above. This irrigation project went out of business years ago.