In 1898, it was rebuilt as a three-cylinder compound with one inside high-pressure cylinder and two outside low-pressure cylinders, as a test-bed for the development of Walter Mackersie Smith's ideas.

Aside from its compound expansion, the 3CC was similar to several other NER classes and they are summarised here: Around 1907 the Class 3CC locomotive was allocated from the Leeds area to Hull Botanic Gardens engine shed where it generally worked fast trains between Hull Paragon railway station and Bridlington.

In 1926 it was transferred to Bridlington although its duties remained unchanged until withdrawal in October 1930.

[1] On 31 March 1920, the Class 3CC locomotive was derailed at York station whilst hauling a passenger train.

The Great Northern Railway (Ireland)'s class V was also a Smith compound.