Thanks for your efforts. The UP maps clearly shows trackage rights, but it's kind of odd; on the map in the public access portion of the UP's website (which your link connected to) the BNSF (ex-Fort Worth & Denver) line from Denver to Dalhart (crossing of the Golden State Route) is shown as a solid line as if it were UP trackage, then a dashed line from Dalhart south. Similarly, the BNSF (ex-AT&SF) Las Animas-Lubbock line is shown as a solid line from Stratford (crossing of the Golden State Route) down to Amarillo, but is shown as a dashed line north of Stratford. However, looking at the employee portion of the website, I find that all this BNSF trackage is shown as dashed lines on the Sunset and Salina Areas maps, and are not listed as UP subdivisions. I'm assuming the UP has trackage rights on those lines, or they wouldn't have been shown on the maps at all. Perhaps the public map was shown that way for PR value, but it doesn't explain why some parts of the lines were solid, others dashed.
Anyway, let's not forget that this whole discussion started because the poor guy got killed. I nearly bought it in similar ways a couple of times early in my career, and I've known others who weren't so lucky. My sympathies go out to his family and friends.