English: Porthmadog - "Blanche" ready to haul the next train to Blaenau Ffestiniog Porthmadog expanded rapidly as a slate exporting port. Welsh slate was in high demand as a construction material in the English industrial cities, and was transported to the new port by horse drawn tramways. The Ffestiniog Railway, opened in 1836, was later converted to steam operation, and trains ran straight onto the wharves. By 1873 116,000 tons (117,800 t) of slate were being shipped out of Porthmadog.