The term Welsh Marches refers to the border area between Wales and England. The railway diverging from the South Wales Main Line at Newport closely follows the border through Abergavenny, Hereford, Shrewsbury and Nantwich. We join a 3-car class 175 Coradia DMU en route from Milford Haven to Manchester Piccadilly on the approach to Newport, the area having only recently been re-signalled to the South Wales Control Centre. From the SWCC, signalling passes to a 1960’s panel signal box at Little Mill and then to traditional mechanical signalling at Abergavenny. Cameras inside all three signal boxes vividly show this technological progression.