These squat, muscular locomotives were built over a fifty-year period, with the later ones coming out in the Robert Stephenson & Hawthorns era.

Contractors, collieries and quarries all found a use for them and they proved to be strong and dependable engines. Two 3ft 6ins gauge examples were constructed for the export market.

The kit includes alternative buffers, chimneys, sandboxes and smokebox fronts to suit most of the variations within the class.