We Had Planes, What About Trains?

Steven, a lawyer from some place called "Brooklyn" (never 'eard of it), e-mails to hep us to an interesting discussion in the comments section of a NY Times post by Steven. D. Levitt (of Freakonomics fame) called If You Were a Terrorist, How Would You Attack?. There are a lot of interesting ideas offered along with comments from a number of people who believe that it's a discussion that we shouldn't even be having.