The Festiniog Railway Company is the owner and operator of both the Ffestiniog Railway and the Welsh Highland Railway. The two railways share the same track gauge and meet at Porthmadog station, with occasional trains working the entire 64 km route from Blaenau Ffestiniog to Caernarfon.
Incorporated in 1832, it is the world’s oldest surviving railway company. Originally belonging to private shareholders, the majority holding is now owned by the charitable Ffestiniog & Welsh Highland Railways Trust.
The Ffestiniog Railway is a heritage railway based on 597 mm narrow-gauge, located in Gwynedd, Wales. It is a major tourist attraction located mainly within the Snowdonia National Park. The railway is roughly 21.7 km long and runs from the harbor at Porthmadog to the slate mining town of Blaenau Ffestiniog, traveling through forested and mountainous terrain. The line is a single track throughout with four intermediate passing places.
The company was incorporated by an Act of King William IV’s Parliament on 23rd May 1832 with powers to build and operate a narrow-gauge railway line from Portmadoc to Blaenau Ffestiniog. Opened in 1836 as a basic mineral tramway with horse haulage and gravity working, the railway transformed itself over the following forty years until it was conveying 130,000 tons of slate a year and pioneering passenger operation on narrow gauge, becoming a world exemplar for narrow gauge railway practice.
According to wikipedia