The Skarloey Railway Slate Quarry, known as the Slate Mines in Duncan Gets Spooked, was a large quarry where all of the Skarloey Railway engines worked. Peter Sam once had an accident with some slate trucks here. Later, some trucks broke free and crashed through some buffers causing an avalanche and trapping Skarloey inside.
After the transfer to larger-scale models for the Skarloey Railway engines, the quarry made more infrequent appearances in such episodes as The Refreshment Lady's Tea Shop and Rusty Saves the Day. It has not been seen since the eleventh season and seems to have been replaced by the Blue Mountain Quarry.
In the Railway Series, after the copper mines had run dry at Ward Fell, it was found that good slate was available in the foothills. During World War II, the Ministry of Defence bought the mines and used it as an ammunition dump.
- The set that was used from the sixth season was redressed later for the Coal Yard.
- On the Talyllyn Railway there was also a watering point a short distance below the bottom of the incline.
- Wooden Railway (cancelled)