Looks like one of the streetcars from the collision that was pressed into service with some box steel and plate steel armor. Looks like a cattle pusher.
How'd you like to look out your side mirror and see that barreling down at you? My favorite streetcar driver before the storm used to take his streetcar and gently nudge cars blocking the tracks with the little 4" rubber bumper on the front, all the while screaming, "move that buggy!" I can only imagine the destruction he would reap in this beasty.
Post apocalyptic New Orleans indeed...
UPDATE- And on the way home from work today, a pickup truck decided to pick a fight with a streetcar:
Streetcar vs. Pickup
Streetcar wins.
