the origin of the railway's name is uncertain. it could refer to the parish of talyllyn, which contains its eastern terminus. or it could come from tal-y-llyn. tal-y-llyn is a large glacial ribbon lake at the foot of cadair idris further east. the gauge of the track is unusual. it was shared by only three other public railways in the united kingdom: the nearby corris railway (which predated the talyllyn), and the subsequent plynlimon and hafan tramway and campbeltown and machrihanish light railway.