The Lickey Banker rating was based on the tractive effort of a Jinty IIRC.
Jinty = 20.830lb = 1
94xx = 22,515lb = 1
9F = 39,667lb = 2
Bertha = 43,300lb = 2
The problem came when the 42xx was trialled as a replacement for Bertha by the WR as at 31,450lb it was rated 11/2 so didn't fit in with what the locals were used to doing.