Dr. Syn is one of the railway's two Canadian Pacific-style locomotives, built in 1931 by the Yorkshire Engine Co., the other being Winston Churchill and has an identical history of design and build.
Originally to have been built by Paxmans as GN outline pacifics (as all previous Romney pacifics), but Howey, an admirer of the American outline, decided to change the order at the suggestion of Henry Greenly. The American style would afford the driver better protection against the inclement weather on the Romney Marsh.
The frames and wheel-sets for the originally intended Pacifics were procured from Paxmans in order to complete the work at New Romney, but even this didn't happen and everything was dispatched to Sheffield for final completion.
Named Black Prince on delivery, Number 10 changed name shortly after the war when Number 9 was re-named Winston Churchill (for obvious patriotic reasons and for display at an exhibition in Canada) and Howey knew that the line could not be without a Dr Syn (a local fictional hero of smuggling stories).
Alterations during the 1980's included — chimney raised and copper-capped, both domes raised, a bell, and a headlight — to give this popular engine a very American appearance.