Welcome to The Railwire!
I don't have any particular knowledge of this area, but have never let that stop me before!
One suggestion is to look through railroad photo sites. For example, this shot from RailPictures mentions KCS leaving its rails for NS and is geotagged.
http://www.railpictures.net/viewphoto.php?id=369336&nseq=30I might also suggest a slight editing of the subject to include the location. It might draw more attention to your specific site and help others in the future if they are looking for similar info on Meridian, MS.
As you progress on your planning, you might consider sharing your progress and questions in a Layout Engineering Report thread.
Again welcome The Railwire.
Best wishes, Dave