My powered underground rail lines cause the game to lock up

My powered underground rail lines crash the game. I don't have enough diagnostic information to be able to explain much about why it's happening, so I've attached some files.

This happens in multiple locations, and doesn't seem to happen aboveground but I don't have long enough rail lines that I'd expect it to happen there.

This also happened in 15w43c, I updated to 50a in hopes of a fix.