This very popular twin cylinder ploughing engine was built as Class BB from 1913 onwards and as Class BB1 from 1919 until the early 1930’s.
The 2” scale model has proved powerful in performance, with all the rugged and well proportioned appearance of the full size engine.
A fully illustrated constructional series of this model, written by Colin Tyler and John Haining appeared in the ‘Model Engineer’ between July 1966 and April 1967 inclusive.

BB1 leading dimensions: Overall length 46” Boiler diameter 5”
Overall width 16 ¾” Boiler length 22 ½”
Overall height 24” Boiler working pressure 75 psi
Approximate weight 240 lb Number of speeds 2