I've seen this train on a couple Youtube webcams. There are specially painted tank cars, box cars and this. Not sure what this is.
Henry
COB Potomac & Northern
Shenandoah Valley
It is Norfolk Southern's Training First Responders trainset.
They are specially painted, and designed cars, that make up a mobile classroom to train fire, emergency medic, and police, on proper response to a incident involving a train, be it a grade crossing collision, engine fire, or derailment.
Interesting tidbit: A couple of years back, they were involved in an unintended grade crossing collision with this very trainset.
Ricky W.
HO scale Proto-freelancer.
My Railroad rules:
1: It's my railroad, my rules.
2: It's for having fun and enjoyment.
3: Any objections, consult above rules.