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 four Northern engines were stationed at Wolverhampton and worked to Chester, then into Oxford over the Oxford, Worcester & Wolverhampton line. The other Armstrong engines worked on south Wales passenger services. The later, Dean engines were more widely distributed. In their last years they were relegated to milk and branch trains.