motterj wrote:I'm just wanting to make sure I "keep my nose clean" if and when I go out railfanning for my first time.
I wouldn't worry about it. I'd stay off any property that appears to be railroad ROW, and away from anything that looks unsafe. In particular, don't take photographs when you're close to a drop-off. It's VERY easy to lose your balance when looking through a viewfinder.
Now, as roadster points out, you may still be on property owned by the railroad. However, if it doesn't look like that to you, it won't look like it to trainmen, nor to a railroad dick. So as long as you don't do anything stupid (aka harmful to yourself or to railroad property or operations) then you won't attract anybody's attentiion.
You can always try waving at the engineer. Always worked for me when I was young, small, and cute.