This week, a Brooklyn teen (who is the son of an MTA conductor) was arrested for allegedly placing pieces of metal onto the subway tracks and causing mini explosions. After our initial report on the incidents, it came out that 16-year-old Keyshawn Brown was part of a group of subway-obsessed teens who have been pulling shenanigans—sometimes violent, always dangerous—on the trains since at least last summer. Even more footage of their deeds has come out now, including the video below, which shows the teens subway surfing on the back of the train, playing with the doors, taking over the loudspeaker, and messing around with the train brakes. As a tipster told us, "They appear to have enough tools to take full control of a train, and they have."

The tipster who put the video up, and goes by the name DJ Hammers, has been capturing videos and other media the teens have been placing on Facebook and reposting it on YouTube since the story came out over the weekend. Like the other witnesses and MTA workers who have spoken to us about the teens, he says he's reported them to the MTA before to no avail.

An MTA spokesman told the Post, "It’s a shame...that the media continues to promote this asinine behavior by posting these videos for others to ­emulate." But it appears transit police only started taking this group seriously after we ran our story on Sunday. "I uploaded [the video] to raise awareness of the issue of this vandal group," the tipster said. "This has been going on for some time and reported to the MTA but little has been done. It appears that only media attention will force their hand."

Hammers explained the difference between real railfans and the teens, who call themselves "Rail Fan Conquerers."

I am not an MTA employee, I am a railfan, somebody interested in trains. As a result I am well versed in how the system works and the implications of these unauthorized people having the tools and keys they have. It is important to draw the distinction between railfan and vandal. Railfans stay within the confines of the law when practicing their hobby and do not engage in this behavior.

Besides controlling train motors brakes and doors, they've also snuck into subway tunnels countless times. A notable incident I remember is when they snuck into the abandoned eastern tunnels between canal street and Bowery on the J line, and left an object on the tracks that sent an adjacent J train into emergency braking. They've also snuck on to trains stored underground along the Queens Boulevard line and moved them around a little bit. They couldn't move them far because of the way the signal system is configured.

They are very brazen, often doing these things in front of people. The concerning part is that they have MTA tools and keys that allow them to manipulate trains. The sound you heard at 1:10 in the video is the sound of them charging the air brake system with a brake handle, which gives them full control over the trains braking system.

These kids are dangerous and have assaulted people before.

Hammer is referring to an incident on February 15th, when a group of six of these teens hit another teen in the back of the head "with a stolen motorman's brake handle - almost 3 lbs of steel." At least one teen was charged in that incident. The mother of that injured teen, Sally, created a Facebook page called PAMTABullying to track their alleged crimes.

A transit source explained to the Post how dangerous it is that the teens have gotten access to train keys: "The tools they have give them a lot of power," the transit source told them. "They seem to have enough knowledge to pull off something very dangerous. These kids have the tools and knowledge to open the doors of the train between stations, put trains into emergency braking, and even hijack a train with passengers on it."

You can check out the video below of the teens causing an explosion on a C train; Brown was charged with criminal mischief, arson and reckless endangerment for placing a metal railsign across the subway tracks at Nostrand Avenue last week.

Check out more on the teens here and here.