A modified version of a standard design by the German manufacturer, The Bug was ordered for use during construction of the original line and the extension to Dungeness. Her short wheelbase and high water capacity made her ideal for such work.
However, once the building of the RH&DR was complete, there wasn't much work for The Bug and she was sold to a Blackpool showman in 1933. He in turn sold her on to the Belle Vue Park Railway, Belfast and there she remained until being sold for scrap in 1950.