Well, in Atlanta there is this thing call a speed limit (I'll have to look, but the posted limit is probably 35 mph) which is the fastest speed you can get away with. Along this section of the road, I would say the average is more like 45-50 mph. I have met other biker on the path (usually not at the RR crossing) and there is not a problem passing by each other. When they constructed the path, they took about 1/2 of a lane and then used some of the existing right-of-way. A lot of it looks like the photo below (taken about 1/4 mile from the RR crossing).