The Monmouthshire Railway and Canal Company was a canal and railway company that operated a canal and a network of railways in the Western Valley and Eastern Valley of Newport, Monmouthshire. It started as the Monmouthshire Canal Navigation and opened canals from Newport to Pontypool and to Crumlin from 1796. Numerous tramroads connected nearby pits and ironworks with the canal.
After 1802 the company built a tramway from Nine Mile Point, west of Risca, to Newport, and an associated company, the Sirhowy Tramroad, connected from Tredegar. Steam locomotives were used from 1829. By 1850 pressure was mounting to modernise the line, and in 1848 an act of Parliament[which?] authorised conversion to a modern railway, construction of a new railway from Newport to Pontypool, and a change of name for the company to the Monmouthshire Railway and Canal Company.
The high volume of mineral activity in the area kept the company in good financial health for many years, but it failed to keep abreast of competing developments, and faced with unforeseen major loss of business it sold the rights to operate its network to the Great Western Railway in 1875. The GWR developed the network, until in the period after 1918 road competition increasingly abstracted passenger and non-mineral goods traffic. Passenger operation ceased in 1962.
The Eastern Valley Line closed completely south of Cwmbran Junction in 1963, but the Western Valley Line was sustained by the continued operation of British Steel's works at Ebbw Vale. A passenger service from Ebbw Vale to Cardiff was resumed on 6 February 2008.