This line is closed. This long branch was built by the Dalmellington Iron Company to reach various pits. It was extended in the 1870s.
A level crossing in Coylton was not allowed and a bridge over the line for the road had to be built.
This line is divided into a number of portions.
This junction was a little east of Burnton Viaduct. The main line from Ayr to Dalmellington was single track and the branch to Coylton was also single track. The Coylton Branch (Dalmellington Iron Company) route was approached from the east and turned north, passing through Potterston Junction Loop to run north east by Martnaham Loch to Coylton.