Both classes proved to be underpowered in this role and many examples were sold as light shunters during the First World War.

During the first few years of the twentieth century, the London and South Western Railway became concerned about losses incurred on several branch and short-distance passenger services, and began to experiment with the use of steam-powered railmotors.

As an alternative Dugald Drummond designed a class of small 2-2-0 tank locomotives, based on the railmotor power units, which could be coupled to one or more carriages to cater for different levels of load.

[4] In 1913, Robert Urie ordered that four examples of the C14 class should be rebuilt as 0-4-0 tanks and the remainder withdrawn as they became in need of heavy repairs.

In 1916, the War Office bought seven members of the C14 class (including one of the rebuilds) for use in various munitions facilities and dockyards.