The engines also had long-travel piston valves, Maunsell's own design of superheater and side-window cab, and other detail alterations.

The locomotives were used on express trains on the South Eastern main lines from London to Dover, Ramsgate and Hastings.

They remained on these duties until the mid-1930s when they were gradually replaced on the heavier trains by the older "King Arthur" and newer "Schools" classes.

The transfer of Bulleid "Light Pacifics" to these services in the early 1950s made the class largely redundant.

Some were briefly transferred to Eastleigh and to replace worn out locomotives on cross-country services, but most spent their careers between London and the Kent coast.