a group of girls so painfully hott that it hurts, in a train pose. not to be confused with grinding because it isnt a lesbian type thing. its a "we're so sexy we just need to get in a hott line and be captains of bang trains" type thing.
BEWARE, there are those who try to make bang trains but they really arent legit trains because you have to be hott in order to make one (SO NO DANA HOES)
blake: hey, we're sexy and its lunchtime. lets make a hott bang train to use up some time. and take pictures.