[hueving]

TSA isn't really for hijack protection, that was solved quite quickly after 9/11 with effectively impenetrable cockpits.

It's really for preventing destruction of the plane itself. A large bomb on a train underground could cause way casualties, which is why the strictness of the TSA is puzzling.

[joering2]

If it really puzzles you then read a little bit on Michael Chertoff and immediately all pieces of the puzzle will click.

Hint: its all about money.

https://en.wikipedia.org/wiki/Michael_Chertoff

Google is your friend but this is good piece:

http://www.washingtonpost.com/wp-dyn/content/article/2009/12...