 The arrival at Blaenau Ffestiniog of the LNWR in 1879 and the GWR in 1883 was responsible for the steady decline in the slate traffic carried by the Festiniog Railway and by Portmadoc shipping.Some slate had been carried via the Festiniog Railway, the Croesor & Portmadoc Railway and the Cambrian Railways after the latter's line had been opened between Barmouth and Pwllheli in 1867; this traffic was diverted to the exchange yard established between the Festiniog Railway and the Cambrian Railways at Minffordd in 1872.By 1925 less than five per cent of Ffestiniog's slate output went out by sea.