I was always drawn as a child to what was described in a book(I think an OS Nock book called Railways, the years of pre-eminence) as "Golsdorf's masterpiece", a 2-6-4 tender engine built for the Austrian Imperial railwway. A quick scout on google bought up class 310 as a better description.
I've always thought the Schools Class had a certain power and impressiveness about them - especially before being fitted with smoke deflectors.
EDIT: typo