In the early 19th Century Welsh spelling had not yet been formalised and Anglicised spellings were frequently used for place names. As a result of this, the Act of Parliament which brought the Festiniog Railway Company into being used just one F in Festiniog. This remains the legal title of the Company. Changing it would require another Act of Parliament.

The correct Welsh spelling of Ffestiniog uses two Fs. The Festiniog Railway Company continued to use just one F for many years. However it now uses the double F spelling for most purposes, only using the single F version where the legal title of the Company is required.

Since the single F spelling was in use for over 150 years it forms part of the heritage of the Festiniog Railway. The Heritage Group therefore uses the single F spelling in its title.

For this web site we have used the single F spelling throughout except when referring to place names or other web sites.