"Sybil" is a 0-4-0ST built by Hunslet of Leeds in 1903. Sybil was used by the Pen-Yr-Orsedd Slate Quarry at Nantlle near Caernarfon until 1959. BMR purchased her in 1963 then once rebuilt was used to haul the first trains here in 1980 comprised of just 1 carriage. Not used since 1981 the locomotive was fully restored in 2012 with extensive boiler work carried out. Sybil rests in the museum at Pontsticill.