The line was built in stages, and originally opened as far as Galston on 9 August 1848.[1] The branch was extended to Newmilns on 20 May 1850,[1] and finally reached Darvel much later on 1 June 1896.[1] Shortly after, on 1 May 1905, the line ceased to become a branch and became a through line to Strathaven and beyond when the Glasgow and South Western Railway and the Caledonian Railway opened a jointly run line.[1] However, despite being a through line, no trains ever ran between Kilmarnock and Strathaven,[2] instead the two companies took it in turns to run the line between Darvel and Strathaven every six months.[2]
The line east of Darvel was never successful and closed in 1939,[1] with the rest of the line closed to passengers on 6 April 1964.[2] Little evidence of the line still exists today, aside from the occasional embankment and cutting along the route. One notable landmark is a 26-arch viaduct in Newmilns, part of which crosses the River Irvine, and most of which cuts through the middle of the town.[3]
Lewin, Henry Grote (1925). Early British Railways. A short history of their origin & development 1801-1844. London: The Locomotive Publishing Co Ltd. OCLC11064369.
Stansfield, G. (1999). Ayrshire & Renfrewshire's Lost Railways. Ochiltree: Stenlake Publishing. ISBN1-8403-3077-5.