A new book by Dave Southern and the late John Keylock and published by The Welsh Highland Railway Heritage Group describes the history, operation and closure of the Bryngwyn branch and its development into today's slate trail.
The Bryngwyn "branch" was the main line under the original North Wales Narrow Gauge Railways Act of Parliament.
Within a matter of two years, it had been relegated to a branch despite generating more revenue from slate traffic than the new main line. Named after an adjacent farm, there are a number of villages in walking distance. However, its main function was for the slate traffic arriving from the incline, at Bryngwyn.
From this isolated terminus, the cable-worked double track Incline led up to a point known as Drumhead (at Fron Heulog), where the tramways from the quarries converged. More here