Intro: These articulated 2002-2004 TMCC engines look great, are well proportioned, 031 capable, and sound good. Sadly the OEM smoke funnel is a 2 piece cast zinc affair (PN 6SP-8077-201) with a single very restrictive passage feeding twin stack openings. The boiler has a cast in “splitter” wedge intended to split the flow to both stacks. The smoke output is anemic at best, even after the Mike Reagan mods. And the splitter wedge pushes smoke forward from the front stack, which looks totally ridiculous. This condition affects all LM Challengers in this era, #6-38021/22/23; WP/WM/UP. It is typical of most mid-2000’s TMCC era articulated locomotives with twin stacks.
About 2 years ago I custom made a brass funnel which vastly improved the smoke production. It was a labor of love, took hours to make, and is not the kind of thing the average hobbyist is likely to want to do. So I decided to see if I could design an inexpensive 3D printed version that would be plug n' play, do the same thing, and be readily available.
So; The Fix: To make this engine smoke realistically it is necessary to radically open up the smoke passages, and manifold the feeds separately to both stack openings, so as to balance the flow to each, just like the real thing. This custom 3D printed funnel provides the perfect solution. First it has an upsized ¼” spigot to flow approx 50% more smoke from the smoke unit. Second it has a generously sized oval shaped main center manifold. Third it has two separate 5/16” vertical smoke pipes, one feeding each stack. The oval main manifold is sloped slightly downwards to the feed spigot, so that smoke fluid naturally runs directly into the smoke unit, regardless of which stack is used to fill it. It has a built in recess notch to clear the OEM splitter wedge, and a support bracket which rests near the middle of the smoke unit PCB. There are two mounting tabs with holes to locate the funnel using the OEM front smoke unit screws.
This picture shows the unit mounted on top of a typical OEM Challenger 8057-200 smoke unit:
The video clip below shows the creation in operation. Way better than the OEM junk!
So if anyone out there is interested in the same fix, shoot me an email and we will see what we can do. My email is in my profile. 
Rod
