Clyde,
Let's see. The UP at one time had quite a narrow gauge system, so that's gotta make it OK.
Secondly, any time anyone ever has a chance to see 3985, it just has to happen. It's just that simple.
I wasn't aware they were running next month. Thanks for the heads up.
As for photographing 3985, a place like Longview sounds like just the spot. Chasing that beast is a whole different game from pacing a narrow gauge train running at 10mph.
Good luck, I'm sure someone can give you some hints. Planning ahead is a good thing.