The Yorkshire Engine Company of Sheffield finished the job of building this loco by finally assembling the parts, accrued during a chequered history for two new engines for the RH&DR.
Originally ordered from, and started by, Davey Paxman then continued at New Romney using boilers from Krauss in Munich. Designed from drawings originated by Greenly, completed by A.L.S Richardson and based on Canadian Pacific practice. The Canadian style was chosen by Howey as it was felt that the larger cab would give the driver better protection against some of Kent's fine summer weather, than the British styled locomotives. He was also a fan of and visitor to the Canadian Pacific Railway. When the engine emerged onto the RH&DR in 1931 she came complete with a very 'American' Vanderbilt tender and was named Doctor Syn, after the Dymchurch smuggling-vicar created by Russell Thorndyke.