The Prototype of a Mixed Traffic 0-4-0 Class on my fictional railway, the Oldcastle & Bluebell Valley Railway.
The prototype performed well, but there were some shortcomings that were resolved for the fist standard member of the class, namely lengthening the wheelbase so it would stop bucking like an industrial at speed.
(I have yet to think of a lore reason, but it is entirely accidental that it is in NWR Blue. None of these in my AU ever went to Sodor, as far as I know)
Inspired by this design both IRL and in my AU, the logic here was that “Surely my podunk rural freelance railway is smart enough to build a class of mixed traffic 0-4-0s” and they are. The class they end up building lasts to BR and is often used as a test bed for modifications and experiments.













