This signalbox (once known as Cadoxton Junction) was situated on the Vale of Neath line, which ran from Swansea Docks (with a connection to the L.M.S.) to Aberdylais, Resolven, Glyn Neath, Gelli Tarw Junction, Aberdare and Crumlin (H.L.). Adjacent to the signalbox was Neath Riverside station and an overbridge carrying the South Wales Main Line. The Neath and Brecon line branched off to Neath Yard, where it became single track, running to Colbren Junction, Brecon and Talyllyn Junction. By 1947 passenger services on the Vale of Neath line from Swansea East Dock and Neath Riverside (inclusive) to Aberdylais and beyond had been withdrawn (Neath General to Aberdylais and beyond continued until 1964), leaving only a service from Neath Riverside to Brecon plus some school trains from Neath Riverside (which was close to Neath Grammar School) onto the Vale of Neath line towards Aberdylais.
Two box diagrams are provided - one box diagram showing the position in April 1956, traced from an office copy held by Kidderminster Railway Museum and the other box diagram is a photograph of the coloured diagram from the box (as a bit-map it is best viewed at 100% scale) and shows a rationalised layout in April 1969 when all passenger services had been withdrawn leaving only 11 of the 38 levers operating, three of which were simply worked to maintain locking. Each branch was being operated as a siding - to Craig-Y-Nos on the N&B and Glyn Neath and Penaber on the Vale of Neath.
Both box diagrams are reproduced by kind permission of Kidderminster Railway Museum.