South Durham and Lancashire Union Railway

The viaduct over the Tees Valley in 1858

The South Durham and Lancashire Union Railway (SD&LUR) built a railway line linking the Stockton and Darlington Railway near Bishop Auckland with the Lancaster and Carlisle Railway (the West Coast Main Line) at Tebay, via Barnard Castle, Stainmore Summit and Kirkby Stephen. The line opened in 1861 and became known as the Stainmore Line.

The Stockton and Darlington absorbed the SD&LUR, and the Stockton and Darlington became a constituent of the North Eastern Railway. The line closed in stages between 1952 and 1962. A short section of the line at Kirkby Stephen East station has been restored by the Stainmore Railway Company.