The Kilbirnie branch from Kilbirnie Junction, known as Giffen from 2 October 1889, was opened for goods traffic on 1 November 1889, and to passengers on 2 December 1889. Although Kilbirnie was a significant town, with a population of 3,405, the dominant feature of the branch was the ironworks at Glengarnock (and also a chemical works there), situated on the west side of the G&SWR main line. The new branch crossed over the G&SWR line and there was a large siding complex at the ironworks, already served by the G&SWR.