Most likely the aspects you will be using are:
There are many more in the UP rule book but they are mostly ex SP and CNW.
You might also have to look at BNSF signals since the UP operates on the BNSF in parts of the PNW.
Dave H. Painted side goes up. My website : wnbranch.com
My layout will be modern era and the location is in the Pacific Northwest
Era matters. Prior to about 1985 they were in the UP rule book. Between 1985 and about 2000 they were in the system timetable and after 2000 they were in the System Special Instructions.
Location matters. With every merger the railroad gained a new signal system so additional aspects were added. For any aspect and indication there might be 5 -10 variations in aspects, but each variation might only be used on a certain part of the railroad. The former CNW may have had a specific type of signal only used on the ex-CGW parts of the CNW. It will be in a post CNW merger UP signal listing, but only used on a small portion of the system.
Googling "UP signal aspects" will give you several different resources.
https://www.cram.com/flashcards/up-signal-aspects-aspect-indications-2484328
http://www.lundsten.dk/us_signaling/aspects_up1988/index.html
http://signals.jovet.net/rules/UPRR%20Signal%20Rules.pdf
Try this http://signals.jovet.net/rules/UPRR%20Signal%20Rules.pdf
Hi MRRDER'S
I have a question for you, I want to have a good signal system for my layout, first of all I want to learn the UP signal aspects, where can I find information on this subject? thanks Guys n Gals.