We examine Bachmann’s narrow gauge mallet and find uses for the loco other than On30 at:
http://www.55n3.org/locomotives/mallet/
The Mallet comes close to the plans of this 1906 Great Northern 2-6-6-2 in HO scale. Just needs new domes, cab fittings and the tender narrowed.
We also look at in other scales.
Thank you if you visit
Harold