Working on the Chain Gang

I have no idea what these guys are doing, I doubt they do too ha ha. However, about once a month a group of guys shows up on the tracks with that thing that looks like a roto-tiller that glides on the tracks and they make some kind of adjustments. Perhaps they are straightening out the tracks or smoothing out some rough spots. Regardless I just can't imagine what that darn machine does. It never seems to be powered up. Never making any noise. The guy just pushes it along. It seems quite heavy too cause when a train comes along, like every 5 minutes, it takes two guys considerable force to move it off the track.
Anyway, this is day 6 of my one week of not carrying my camera around so this is a photo from my 16th floor apartment looking out onto the railroad tracks.