The street that runs between the building marked as "Concert Hall" and the white stone building is Peachtree Street, so this is that part of town slightly west of what is known as Five Points. The railroad "gulch" in the picture was covered up in the 1920s by a system of viaducts. Directly across from Peachtree Street ran Whitehall Street. There is a very famous Barnard photo showing a building marked "Negro Sales" which was on Whitehall Street, directly across from the signal mast you can see over the building next to the car shed, which was the depot for one of the four rail lines that ran through Atlanta in 1864.

The building behind the mast is Atlanta's first Fire Station HQ, located alongside what was then called Broad Street. The lens Barnard used to photograph these scenes greatly flattened the perspective, so that some objects appear closer than they really are.

The guy on the wagon in the foreground only seems to be half there. His head is not articulated and the ground behind it is visible. Strange.

[This is how people look when they move during a time exposure. - Dave]

According to Rail Georgia that building on the right is Atlanta's first Union Station.

Atlanta's first union station, constructed in 1853, stood in the block now bounded by Central Avenue, Wall Street, Pryor Street, and Alabama Street (next to today's Underground Atlanta). Designed by civil engineer E. A. Vincent, it was initially known as the "passenger depot" but came to be better known as the "car shed."

I wonder where this is? I'm assuming it's close to contemporary downtown Atlanta (the Underground Atlanta houses the "zero-mile" marker) and it was the center of the railroad traffic, at least after the war...

Looks like smoke from a chimney and/or a scratch on the negative.

[Nope. We are talking about the articulated mast seen below. - Dave]

What's the very tall pole at the back left of the photo? Lightning rod? Flagpole? TV antenna?

[My guess would be signal mast. - Dave]