Aside from the UP rails connection in Portland itself (where 4449 must travel over UP rails to get out to Portland Union Station), the line crossing the Columbia River near Wishram down to Bend has a significant segment OWNED BY UP RAILROAD. This segment was UP rails when the 'railroad war' occurred there. It has been UP owned ever since the Harriman/Hill era, and continues with BNSF running over the UP owned segment (and BNSF owning the rest of the line to Klamath Falls).

You can see the UP owned segment of this line on this UP map:
[www.up.com]
The dashed line segments are UP trackage rights, but the solid lines are UP owned segments. If you doubt my comments on the dashed/solid segments, just examine this similar Washington map and look at the segments where UP and BNSF go north of Portland to the Tacoma area.