The Merionethshire Railway (MR) was a proposed 1 ft 11+3⁄4 in (603 mm) and 4 ft 8+1⁄2 in (1,435 mm) dual gauge railway in south Caernarfonshire (now part of Gwynedd), North Wales, United Kingdom.
1), three miles one furlong eight chains and thirty-five links or thereabouts in length, commencing in the parish of Festiniog in the county of Merioneth by a junction with the Festiniog and Blaenau Railway, and terminating in the parish of Maentwrog, in the same county, in a plantation on a farm called Hendre Mûr, belonging or reputed to belong to Morgan Lloyd, Esquire.
c. ccvii), authorising it to build from Bala Junction to Blaenau Ffestiniog where it aimed to tap the town's prolific slate output.
By proposing the line its backers sought to threaten the Festiniog Railway into reducing charges and raising service levels.
[6] The Bala and Festiniog Railway (B&FR) reached Llan Ffestiniog in 1882 and converted the F&BR to standard gauge in 1883.