Cilgwyn quarry was connected to the gauge
Nantlle Railway by a pair of
inclines that dropped from the Cilgwyn mill level through Gallt-y-fedw quarry to a junction at
Talysarn Uchaf. Internally the quarry had an extensive network of gauge tramways. These served the three main pits and the waste tips. A mile-long tramway ran from the mills round a horseshoe curve to a waste tip on the north side of Mynydd y Cilgwyn. In 1923 a connection was made from this tramway to the line connecting Fron quarry to
Bryngwyn. This allowed slates to be dispatched from Cilgwyn onto the
Welsh Highland Railway, avoiding the need to transship slates from the internal quarry wagons into the Nantlle Railway's wagons. The quarry used at least three steam locomotives internally from 1876: The steam locomotives were replaced with a number of diesels. One of these –
Ruston & Hornsby works number 175414 of 1936 – survives in preservation at the
National Slate Museum in Llanberis where it carries the name
Cilgwyn; it worked at Cilgwyn quarry between 1936 and 1940. The quarry ceased to send slate via the Welsh Highland Railway in 1935 when a new road was constructed down to Talysarn. From that point all slate left the quarry by road. == References ==