Following completion of this project, the sections of line between Barrhead and Kilmarnock (with a crossing loop at Lugton) and Annan and Gretna (controlled from Carlisle) were singled.

Re-doubling of the Annan to Gretna section was completed in August 2008, controlled from Dumfries Station signal box.

In early 2009, work commenced to re-double the line between Lugton and Stewarton based on the 2008 plans published by Network Rail.

Further work is currently underway to re-double and electrify the branch line from Thornliebank to East Kilbride.

[4] With the exception of the electrified section between Glasgow Central and Barrhead, all other services on the line are operated using the British Rail Class 156 diesel trains.

Electric train services are also provided between Glasgow and Troon and Ayr via the Ayrshire Coast Line.

From the December 2015 timetable change, new Scotrail franchisee Abellio changed the schedule on the Stranraer line—the service frequency to/from Ayr has increased from six trains each way to eight on weekdays (and from three to five on Sundays), but there are now no longer any direct trains to Glasgow via Paisley—all services now run via Kilmarnock.

There have been several studies recently as to the possibility of reopening Thornhill station, roughly halfway between Dumfries and Sanquhar.