Hi Jeff,
Thanks for the reply. I suspect it will be the gearing too that's responsible for the transformation in running quality. When I ran the Railroad Bagnall Shunter on my layout, I couldn't believe how smooth it ran compared to an older GWR 101 that my daughter has.
I might purchase the Caledonian Pug example as I think it's not a bad model for its age. In the past, the only thing that prevented me buying one was its inability to run slowly or at a modest speed. Small changes = big benefit.
Do you or anyone else know if the chassis and motor can be bought as a complete unit (i.e. minus body) as I could upgrade a super-detailed Nellie bodied 0-4-0 that I have?
Regards,
Paul