...okay, reality check, even if the autopilots get good enough, it'll still be incredibly easy to whack a drone into the train's overhead wires if you have a big enough stick, and now they potentially have to fix the cable, or maybe a blown transformer. Right.
Ängäyge!1!!
I'd call them TrackBlastR.
Now I actually think about it (thanks), what would a drone be doing? Yelling really loudly? Getting footage of people's faces?
It's probably only a matter of time until drones end up equipped with taser units :/ (I honestly don't want to be around when they can actually shoot things...), but besides that I now realize they wouldn't really present a legitimate threat (yet). They'd just be very oversized mosquitoes.
I'd completely forgotten this is America though, where people can and do shoot at stuff they don't like and/or is annoying. That would be significantly more effective than a giant baseball bat (which would definitely look hilarious but be a lot less precise).
Or Napalm?
FWIW it looks like a bunch of Russians had similar ideas 5 years ago and bolted a paintball gun to a drone (apparently with automatic targeting too): https://www.youtube.com/watch?v=8igjcW39T4k
Äxzällänt Äxikyushn!
:-)