Buses replacing trains between Kilmarnock and Dumfries in both directions on Sat 2 Aug.
If you were planning on travelling by train, allow a good bit of extra time for the journey. There are express replacement bus services from Glasgow straight to Dumfries "at peak times". Not sure if Saturdays count as peak.
Here is a link
http://www.journeycheck.com/firstscotrail/

(Click on future engineering works, then 2/08/08, then further information).

Thought you were going to say back down to the 2nd divison there