Teens are not exactly known to exemplify the platonic ideal of straphanger behavior—they're usually too busy hanging off the backs of trains, racing across the third rail, or playing real life "subway surfer" to pay much attention to other people. One such group of teens has apparently been placing pieces of metal onto the subway tracks in recent months, causing mini explosions like the one in the video below.

R32 Train Explosion from Gothamist on Vimeo.

This video, which was filmed this past week, shows a C train coming into the Nostrand Avenue station followed by a small explosion with a fury of sparks, apparently due to a metal object on the track. A tipster told us, "I had just come across this video on my Facebook feed...The object, according to the comments, is a rollsign box, which is the destination sign that you see in the older trains."

A subway motorman reposted the video on Facebook with some details: "That kid keyshawn ....He is out again and put a fucking rollsign box on the tracks," wrote the motorman, who later deleted his comments. He added:

Some kid who hangs with 'these kids' who just got locked up posted it...They got locked up for almost fatally killing me in the back of my head with a break handle they already got locked up and THEY STILL HAVENT STOPPED...And they spent a couple days in Rikers and still won't stop.

The teens involved in both of those incidents are also allegedly the same ones in the video below who were electrocuted while putting a sign on the tracks back in February.

We've contacted the motorman for further comment about the incidents.

Update: The MTA gave this statement, and confirmed that the NYPD is investigating.

It is outrageous that these people endangered the lives of our employees and customers with this prank. This incident was not only extremely dangerous but it also affected service for more than an hour during the morning rush, disrupting the commutes of thousands and thousands of customers. We are working with NYPD to find these perpetrators.