The Summit Level is a straight on the Glyncorrwg Railway (NPRN 34840), circa 860 metres long, on the Glyncorrwg Railway (NPRN 34840), passing north-north-west to south-south-east (from National Grid Reference SS78759854 to SS79199780) across the northern summit area of Cefn Morfudd. The straight passes through an embankment (NPRN 309288), through a cutting (NPRN 309291), over a bridge (NPRN 309293) and along an embankment (NPRN 309295), ascending to and descending from the summit by inclined planes (NPRN34842 and NPRN 34841). The feature is visible on Ordnance Survey County series (Glamorgan XVI.10 1878) map.

Stephen Hughes and Paul Reynolds (1989) 'A Guide to the Industrial Archaeology of the Swansea Region' Association for Industrial Archaeology.

RCAHMW, 17 October 2011.