So I have been roped into helping a great guy who was an obsessive G scale guy but downsized to On30 indoors. He is the one who convinced me to go On30 indoors instead of doing my 1:24 layout indoors. Anyway his favorite locomotives is the converted Unitah narrow gauge Mallets after they went to Sumpter valley and had the side tanks removed.
As a model he likes the shorter 2-4-4-2 as opposed to the longer 2-6-6-2. But he did not like the wimpy skinny boiler of the Bachmann model and I had to agree it is too small. Well I have acquired one myself as do a couple others in our G scale club and we are all kinda wanting a larger boiler. There was an article in one of the On30 Annuals were a guy made a larger boiler with pipe. Using that as a starting point I set out about designing a new boiler for the Mallet. One thing with a larger boiler, the cab needed to be raised. And also a redesigned firebox. The guy in the article cut the old firebox off and just reused it. Great easy make shift solution but at the end of the day its way to small for that large of a boiler. So I made a boiler similar to that of what is on narrow gauge 4-4-0 and 2-6-0 locos where the fire box sits between the drivers and it much narrower.
The first attempt needed some tweaking upon a test fit. So the second draft is being printed by Mike Williams today. But here is couple computer renditions of what the second draft will look like.
I will use a combination of salvaged parts from the Bachmann and new parts from Wiseman to give it some detail. I will post a picture after I get the boiler fitted and then when its done.