Anyone think of something other than a trigger? To be used as described in the article, their would have to be a receiver as well. A line of sight trigger like your garage door opener has. Put the trigger out on the track somewhere, start a timer and activate some seconds/minutes later.
I did not see in the article where this was pointed.
Was it pointed up? Across?
What was to be read from the broken beam? motion down the track or people walking the track?
Either way, Al-Queda is here, and it's Bush's Fault!!
Oh, Yeah, Reagan's fault, too!
There is the possibilty that such preliminary steps have been taken to trigger explosions on a number of areas throughout the US.
If a terrorist was making a map that could be purchased at the local store he was more likely making a map of targets where some work was already done.
What if we have specialized cells which do separate things. One group might only do electronics, while another does the explosives. A master map would be needed to pass along.
Such a device suggests to me that we are being set up for an attack at a time of the terrorists chosing.
Perhaps park a rental truck full of explosives in a garage beside the tracks, and use the IR beam to trigger the explosion? Finding something like that in the tracks is definitely worrisome.
Could it be for monitoring the trains? For example, checking to see what time the trains go over that particular spot.
Traffic counting for a school project?