I've witnessed this, too...and it's pretty hard to step up to be the hero when everyone else is cowering around you - you realize pretty fast that no one has your back. Realistically, the best I could think to do would be find a conductor or call 911 (not that I would expect immediate help). Also, in real life, I have been there and tried to make some kind of eye contact with one of the kids to signal "do you want to move back? Do you need help?" But thats easier said than done in practice. We need more security on SEPTA, just like Amtrak has on regional trains. Aside from the obvious cost issues why isn't there a SEPTA security officer on each train, patrolling up and down?