While there were many small standard locomotives for the narrow gauge lines in quarries, some customers had special requirements. One of these was the Moel Tryfan quarry in North Wales that had an access tunnel that required the locomotives not only to be narrow, but also to have a maximum height of six feet (1.829 mm). So Hunslet delivered two locomotives in 1902 and 1904 which were based on the Alice class and tailored to these requirements. The first one was named “Tryfan” after a nearby mountain and the second one carried the name of Cadf#

an, a Welsh saint.

Like the Alice class, they were 0-4-0T saddle tank locomotives. To reduce their height, the floor of the cab was lowered as much as possible. To protect the crews in the tunnel, the cab had no windows on the sides. As a result, “Tryfan” had a total height of exactly six feet, while “Cadfan” was even a bit lower. During their lives, at least “Cadfan” was once loaned to a neighboring quarry. Both were scrapped in 1941.