Built by the Caledonian Railway and opened in 1869,[citation needed] it provides a link between Glasgow and Edinburgh through the mining communities of Lanarkshire and West Lothian.
The line was built by the Caledonian Railway to serve a variety of industrial locations, including collieries, iron mines and an oil works near Addiewell.
It followed the route of an earlier private industrial line built to serve a number of mines in the area.
[citation needed] The line became part of the London, Midland and Scottish Railway at the 1923 Grouping, then the Scottish Region of British Railways upon nationalisation in January 1948.
None of the industries once served by the line still survive - the last of the collieries served by it (at Polkemmet) having closed down in 1986.