I have been riding along RR tracks in California for over 40 years. No one, be it farmer, sheriff, city cop, landowner, RR company cars, RR company trucks, RR company police, train conductor, or hobo, has ever even hinted that riding along the tracks is illegal and / or that I could get arrested.

The RR in my area, BNSF, has some areas of tracks near town posted "No Trespassing", and in these areas few people go, and they are pretty much impassible from non-use. But that leads me to believe that the other thousands of miles of track that are not posted, have no restrictions. They get used daily by joggers, bicyclists, and dog walkers.

Maybe someone who is an expert at this stuff could correct me if I'm wrong, but my understanding is that the land used for tracks is technically owned by the landowner, but the railroad has an "easement" allowing them to use the land, but only for uses involving trains and track maintenance. So I'm not sure if the railroad would have authority to tell someone to leave if it's not their land, or why they would even care. The one time a RR employee approached me, was because he thought I had parked my car too close to the tracks and asked me to move it. However, he did not tell me I was trespassing or ask me to leave. I have seen kids on dirt bikes run off by farmers occasionally, I suspect motorcycles is where the line is drawn.

So long story short, after 40+ years, I still don't know for certain whether someone can be cited for trespassing when riding a bicycle along RR tracks or not, but my experience has been "as long as you aren't breaking some other law, or pissing someone off, no one will bother you."