Wait, I call BS on this post. The thought had crossed your mind of multiple stabbings on a train? because of recent news stories? What news stories exactly that would make you worried to take a train all of a sudden? When someone uses a one off, out of the blue extreme situation like this to try and make a doomsday prouncement and declare something has to be done about this? About what? There have been these kinds of things in our long past, pubs being blown up by the IRA etc.
So I get highly suspicious as to the motive of someone when using such situations as a threat of, something's gotta be done,' type thing.