Ray Breyer
Modeling the NKP's Peoria Division, circa 1943
Tom View my layout photos! http://s299.photobucket.com/albums/mm310/TWhite-014/Rio%20Grande%20Yuba%20River%20Sub One can NEVER have too many Articulateds!
Hugh:
I'm not sure about the 4-6-2, but my USRA mallet dis-assembles like most brass articulateds, a couple of screws under the cab and a central screw under the second cylinder set.
I would assume that like most 'brass' models, your 4-6-2 should come apart in much the same way--two screws either at the back or under the cab, and a central screw through the cylinders, which also holds on the front truck. After that, the cab and boiler should just lift off. As to DCC conversion, those 'powerhouse' models have solid metal boilers, so I don't know what kind of room you'd have between the motor and boiler for a decoder. And drilling for a headlight could be a major challenge, if your 4-6-2 like my mallet has a solid boiler casting.
Tom
You might find this useful:
http://www.wiringfordcc.com/ol2882.htm
Tom -
Hugh