Thank you.  The plastic GP 40 fuel tank cover is a very snug press fit.  It took some prying with the small flat bladed screwdriver to get the fuel tank moving off of the metal fuel tank structure underneath it.  Eventually it slid off.  There are two screws holding the body and frame together.  It would be great if Bachmann would show this on their drawing!  Once the screws were out, I had to ease the frame past the coupler mounts... a little back-and-forth action.
The only problem that I had was when I dropped one of the screws!   
I spent at least 5 minutes on hands and knees searching forth the danged lost screw.  Eventually I gave up.  For now, the body and frame are held together with only one screw.  Usually I disassemble things over an inverted copier paper boxtop, but this time I was in a hurry and paid the price... only taking a couple of screws out... you know the famous last words.
Anyway, thanks to you all for the answer 

Hi,

How do you remove the body of the current Bachmann GP 40 ? 

I looked at the Parts & Service section, but it has the same exploded view that comes with the GP 40.  It has no indication of how to take off the body.

I tried turning the locomotive over and inserting the blade of a small screwdriver between the body and the metal frame - - to see if I could release some tabs, if there are any.  I repeated that several times; however, the body is stiff and I did not want to break it.

Do I have to remove the plastic fuel tank?  I did not want to force it off in case it is fastened to the frame with screws.  The exploded view does not even show the fuel tank!

This is my first day on this site, and it is because of this problem removing the GP 40s shell.  I hope this question has not been asked before, but I did not want to search thru 289 pages of discussion questions.

Happy modeling, TomM