See through fan grills?? Here's the Atlas article on them in case you haven't seen it.http://www.atlasrr.com/ARNweb/News/0407/gp40-2.htm
And different and better road names, and plus they more prototypical stuff like the chessie unit details, and the plus the y have Conrail :D
Tjsingle
The doors under the radiator area are different. Sight glass on the engineer's side. Blomberg-M trucks with rubber pads instead of leaf springs, and shock absorbers (as appropriate). Cab interior should be different, Dash-2 electrical cabinet and control stand.
The step wells and other frame details changed over the production run.
Mike WSOR engineer | HO scale since 1988 | Visit our club www.WCGandyDancers.com