The entrance to New Rossydd quary adit at top level of Croesor tramway. Quarry flooded and very dangerous. Slate wagons hauled up incline in adit using a special gripper wagon called a "Megryn".
The Megryn was used to haul wagons along the adit, not up inclines. The internal inclines were (I think) of the type that have a level platform for the wagons.