Two types of sign posts can be found alongside most railroad tracks: the whistle post and the mile post. Whistle posts indicate upcoming road crossings to the engineer, requiring use of the locomotive's horn, while mile posts denote mileage from one end of the line.
Georgia law requires whistle posts to be placed 1200 feet before a crossing, but on the long-unused former L&N Railroad line between Blue Ridge and Ellijay the posts were spaced at that railroad's old standard of 1500 feet. As part of a 1997 effort to reopen the line for Georgia Northeastern trains, a group of NARCOA volunteers decided to help get the posts in compliance.
Every one of the old concrete whistle posts had to be replaced. Because most were damaged, and pulling them from the ground tended to cause further cracks, the railroad decided to replace them with metal signs.