A project to restore a 108-year-old steam locomotive into working condition has been completed.
The engine - named the Hugh Napier - started work at Penrhyn Quarry in 1904 and was decommissioned in 1954, where it was abandoned and left on a railway siding.
It avoided being sent for scrap and was donated to the Penrhyn Castle Industrial Railway Museum in 1966.
Former quarryman Iorwerth Jones and the team at the museum spent many years collecting the parts necessary to make the Hugh Napier run again. Although Mr Jones died before he could see the project completed, he left a comprehensive list of the required parts behind.
Today, the restored engine will be unveiled and re-named in a ceremony at the Ffestiniog and Welsh Highland Railway.