The Kilmarnock and Troon Railway was a local line, and as larger concerns extended their area of influence, the Glasgow, Paisley, Kilmarnock and Ayr Railway (GPK&AR) leased the line from 1846, and built connecting lines so that it became an integral part of their network. The alignment at the second Laigh Milton Viaduct was still unsatisfactory and in 1865 a third viaduct was built further south. The GPK&AR was taken over by the Glasgow and South Western Railway and the line remains in use today (2013), owned by Network Rail. Passenger and freight trains operate over the route.