806–825) was Joseph Armstrong's last design of 2-4-0 mixed-traffic locomotives for the Great Western Railway, built at Swindon Works in 1873.
A further 20 similar locomotives were added by Armstrong's successor William Dean in 1881-2; numbered 2201–2220, these had modern domeless boilers (see GWR 2201 Class).
Most of the Armstrong locomotives worked in the Southern Division, and carried Sir Daniel Class boilers; only Nos.
806, 807, 810 and 821 were Northern Division engines, and these were in due course fitted with Wolverhampton boilers.
The other Armstrong engines worked on south Wales passenger services.