This footage is of the band  Atomic Tom, and according to the video the band had their instruments stolen, so they decided to jam out on the New York City B train with their i-phones. Its a pretty cool concept and the sound is surprisingly good coming from instrument apps on the phones. The description for the video said that the footage was taken with 3 i-phones and was all done in one take and 100% live. That is pretty impressive. Yay technology!