Incorporated on 28th July 1884.
Formed originally as the Barrmill and Kilwinning Railway in 1883, built to connect the Glasgow, Barrhead and Kilmarnock Joint Railway with the Glasgow and South Western. An extension to Ardrossan was authorised in 1884 along with the change of name, and the revised line opened in 1888 operated by the Caledonian Railway, who had subscribed to the undertaking. It passed to the London, Midland and Scottish Railway in 1923, some sections having been closed to avoid duplication.
Capital £325,000 in shares of £10 each, loans of £75,000, and debenture stock of £100,000. Increased in subsequent years to 700,000 in shares and £225,000 in loans/debenture stock.