The HO Oldtime Roundhouse 2-6-0 mechanism will fit under the inside-frame 4-4-0 with minimal grinding on the boiler.Harold
I was asked if I was going to do an article. This conversion is a low priority on my list. It is rather simple. The frame slips into the boiler. There is interference at the front of the gear tower. Either the boiler or the frame have to be relieved. The 2-8-0 frame will fit without any grinding so it shouldn't take much. The boiler lug lines up with the frames mounting hole. The Bachmann cylinder block will fit if the channel on the Roundhouse frame is opened to .35 from .31. The two driver is in the same place so the Main rod won't have to be modified. A back mount and PC board mount have to be devised.That is the conversion.Harold