In March 2018, the City of Atlanta announced the final sale of the southside portion of the Beltline Trail that runs between Glenwood Avenue, down and around under the Connector and meeting up with the Westside portion of the trail which was completed in 2017. The tracks have finally been cleared and folks can now be seen regularly using the new interim trail.
My own neighbors took it upon themselves to repurpose this little switch box, turning it into an informal Little Free Library. Enjoy the walk...and bring a book to donate or swap out.
The cache is a small magnetic keyholder.