Hill's Tramroad was a 2 feet (0.61 m) gauge plateway for horse-drawn trams that connected the Blaenavon Ironworks to Llanfoist on the Brecknock and Abergavenny Canal.

[3] It then ran for 3 miles (4.8 km) north east from Pwll Du round the Blorenge hill to Llanfoist Wharf.

[2] The plans to build the forge in Cwm Llanwenarth on the west branch of the Blorenge included replacing a steeply sloped section of the tramroad from Blaenavon by a shallow gradient tramroad along the Pwll Du Tunnel, an extension of an earlier mine tunnel through the hill to Pwll Du.

From the forge it carried wrought iron to the Llanfoist wharf on the Brecknock & Abergavenny Canal.

[7] The double incline ran up and over the hill above the tunnel, with a steam engine at the summit to haul up the loaded trains.