GSF locomotive on NS

[phil]

Can you tell me what original road a locomotive on NS with  GSF markings  came from?
What is GSF?
and what was the extent of this road?

[Railroad80]

GS&F is the Georgia Southern And Florida Railroad..... From Macon, Ga. to Jacksonville Fla, With a branch to Lakecity Fla.  That branch once went all the way to Folley Fla.