I have written a few articles and blog posts about the Hendre Ddu Tramway and related subjects, based on the research for the book:
Catherine Pugh - a short post about the only female barrack keeper in the Welsh slate industry. Published on the Merced Chwarel blog.
Gertrude Russon - who owned Gartheiniog quarry between the wars. Published on the Merced Chwarel blog.
Over the Hills - an article about the connections between the Hendre Ddu Tramway and the Corris Railway. Appeared as a two-part article in the Corrispondent
Esgairgeiliog Quarry - forthcoming article for the Corris Railway Journal