The railway is 13½ miles long and runs from Porthmadog to Blaenau, Ffestiniog. Founded by an act of Parliament in 1832 and opened commercially in 1836 and ran until 1946. Unlike the majority of other railway companies at the time, it was not amalgamated into one of the four main groupings, in 1921, and in 1947 it was left out of British Railways, because by that point it was closed to traffic. The line reopened again as a heritage railway in 1956.