Part of the plateway system connecting various ironstone and coal levels on the NE slope of Mynydd Aberd're with Cyfarthfa Ironworks.
(SO02950518-SO02770524).

1884 (OS 6-inch 1st Edn.): A branch serving workings near Cwm-du, making a trailing connection with the line to upper Cwm-Glo.

1905 (OS 6-inch 2nd Edn.): Not shown.