1924 view versus 2018 view.
This is the bridge that came off of the NP at Adco and connected with the GN siding and then for a time the NP engine terminal near the GN depot. A map is included below all this to help give vision to the situation.
This crop of a topo map shows the NP entering the scene from near top left and splitting, with the right leg connecting to the GN while the left leg continues over the GN for points south.
This map lays out the location of the NP engine terminal and has a note about how there is an agreement between the GN and NP for use of the GN siding for access by the NP to the engine terminal.