Grawen Depot was developed circa 1830 as the central depot on the Brecon Forest Tramroad in place of Cnewr. In 1989 the ruins of stone built cottages, stables and a covered lime shed remained on the route of the tramroad and beside the carraige road.

The limeshed was built in the early 1820s probably by the engineers Joseph Jones of Ystradgynlais & John Jeffreys of Sglydach, and funded by the London Indigo Merchant John Christie (originally from Stirling), as part of the Brecon Forest Tramroad from the Swansea Canal at Cae'r-lan over the uplands of the newly enclosed Fforest Fawr to the Tramroad Wharf near Sennybridge. Most of the lineside cottages were built by the Brecon Forest Tramroad Company in the late 1820s. The buildings were probably abandoned in the 1860s when the tramroad was replaced by the Neath and Brecon Railway.

Sources:
Stephen Hughes, 'The Archaeology of an Early Railway System: The Brecon Forest Tramroads' (RCAHMW, Aberystwyth, 1990).
Stephen Hughes and Paul Reynolds (1989) 'A Guide to the Industrial Archaeology of the Swansea Region' Association for Industrial Archaeology.

RCAHMW, 14 October 2011.