It's not really a bad idea - having a trail along side the railroad track; provided it does not take up room needed for a future second track.

As long as the pathway is plainly discernible from the rest of the trackway, it shouldn't even need an ugly and expensive fence. After all, people do usually manage to safely use sidewalks, without any such fence between them and mad-dog automobile drivers. Why not with a fixed guideway and professionals at the controls.

Of course, my real agenda here, is more public access to more track - for us railfans!