By the late 1850s it was clear that the line was reaching its carrying capacity, while the production from the slate quarries was continuing to expand.

Charles Menzies Holland was acting as locomotive designer for the Ffestiniog Railway and he approached George England who lived near him in London.

England agreed to bid for the contract and in February 1863 he proposed building three 0-4-0T locomotives primarily to his own design.

The locomotives had a low center of gravity and were extremely small to fit within the restricted loading gauge of the railway.

As a result, they suffered badly from priming and domes were hastily fitted in Wales before the locomotives could be run on service trains.

The introduction of the initial locomotives was a great success, allowing the railway to handle the increasing slate traffic and its first formal passenger trains.

After preservation, Princess has remained in her 1946 condition, although cosmetically restored in 1963 and 1981, after which she was displayed in Spooner's Bar at Harbour Station.

In 1980 Prince returned to traffic with superheating and a larger cab fitted and converted to oil firing.

After preservation parts from Palmerston were used to restore Prince and the rusted remains were sold to a group in Staffordshire in 1974.

They also had a longer wheelbase and larger driving wheels than the Small Englands, to counteract the smaller locomotives' "violent vertical oscillations".

[6] New build project Duke, from The Railway Series and its televised adaptation, along with Bertram, are based on the Small England locomotives, more specifically number two, Prince.