North Devon and Cornwall Junction Light Railway
The North Devon and Cornwall Junction Light Railway was a railway built to serve numerous china clay pits that lay in the space between the London and South Western Railway's Torrington branch, an extension of the North Devon Railway group, and Halwill, an important rural junction on the North Cornwall Railway and its Okehampton to Bude Line.
China clay was an important mineral but its weight and bulk required efficient transportation; the material had been brought to main line railways by a 3-feet gauge tramway. Expanding volumes prompted conversion to a light railway -- requiring less complex engineering and operational procedures than a full railway -- and it was opened on 27th July 1925.
Passengers were carried in addition to the mineral traffic, but the business largely consisted of workers at the china clay pits themselves. (Thomas says, "The largest place on the railway is Hatherleigh ... a market town in the centre of a barren countryside, it is badly decayed".)
The conversion from a tramway was overseen by Holman Fred Stephens, the famous owner and operator of marginal English and Welsh railways. Although in construction details typically Stephens this was visually a Southern Railway branch line. It survived in independent status until nationalisation of the railways in 1948, and continued in operation until 1st March 1965.
The northern part from Marland, reconstructed from the narrow gauge railway, continued to carry china clay, but not passengers, until 1982
Sources of Information
-  Wikipedia