Marty, that's plumbing for the steam generator. There is also a stack on the short hood and some vent thingys. I have never seen a good close up shot where you could actually tell what it looked like. Maybe Cal-scale has the part. By the way, ran the heck out of the Berk at Gary's Sunday afternoon. Happy to report that she steamed very well. Gary may be posting some photos tonight. Minor details and she will be headed your way. (I would much rather run her out there with a reefer train in tow than to ship her USPS, but whattaya gonna do).