Regarding the terrorist thing. The train bombings killed 200, the planes
about 3000. You can't drive a train into a packed skyscraper or packed
stadium.

Depends on the train stations. There have been incidents of runaway trains
breaking through stations that are dead ends and going throgh not onlt the
station itself, but also breaking through the other side and going onto the street.

There have also been incidents of trains (mostly freight) going too fast and
derailing into cities. One such indicent in the arly 1980s necessitated the
evacuation of a large part of toronto (Missisauga) after such a train derailed
and dangerous gases got out along with fires.

(note that those were not terrorist issues, but should a terrorist gain
control of a train, it could do a lot of damage).