 Under the Railways Act 1921 most of the railway companies of Great Britain were "grouped" into four large units.The Great Western Railway absorbed a number of smaller concerns within its area of influence, and the Newport Docks passed into its ownership, becoming known as the Great Western Railway's Newport Docks.The Monmouthshire and Brecon Canal was originally two independent canals – the Monmouthshire Canal from Newport to Pontymoile Basin (including the Crumlin Arm) and the Brecknock and Abergavenny Canal running from Pontymoile to Brecon.