Penn Station find was a soda can with a suspicious substance??
Looks like Penn has been reopened - all clear
http://www.wnbc.com/news/5067592/detail.html
IIRC...a few years ago there were soda bottle incidents reported along the tracks in the Philadelphia metro area. On TM at that time it seemed like it could have been a trial run.
Just a thought on the water bottles.... In Beslan the community set up a memorial for the victims with water and soda bottles. When they were being held hostage they were suffering from lack of water.