Track Rights on a shortline?

[Gary S]

Thanks for the replies, gentlemen. I guess I'm looking for a reason to have UP locos on my layout, just for some variety. But of course, I want the reason to be plausible. From Charlie's answer, it seems my shortline would not want to allow the UP engines on our tracks. I'm kind of in the middle on this right now. The good point of allowing trackage rights is I get to have a bigger variety of locos, the downside is I would have to spend $$$ on a couple new UP locos since i don't have any right now.