OK. I'm completely frustrated here. Today I received an Atlas Dash 8-40bw in BNSF Heritage II paint. What a locomotive. The detail is incredible! I put it on my layout in DC mode and it's smooooth! I want to install a DCC decoder, but I can't seem to get the #$@% shell off. There are no instructions to remove the shell. I've already removed the couplers. How do I get the shell off? Help!