There is considerable disagreement about the actual detailed design of the “Penydarren” locomotive but, for the purposes of this page, the captions are as used by Francis Trevithick in his two volume biography of his father. This is the design of locomotive used in the logo of the Merthyr Tydfil Heritage Trust, for the model on the Trevithick Memorial in Merthyr Tydfil and for the famous Cuneo painting. However, when building their replica, the staff of the Welsh Industrial and Maritime Museum concluded that the design was more likely to be similar to the Gateshead locomotive and built the replica accordingly, taking the view that the drawing below was probably the Coalbrookdale design. Given the conflicting written evidence and the lack of any positively identifiable remains, it is unlikely that the mystery will ever be resolved.
