When I was in 6th grade, my whole class went to camp for a week at Mount Palomar.
One of my strongest memories was from one night, when we had a campfire. We were singing songs, and one of the songs (in fact, the only one I remember) was "I've Been Working On The Railroad."
Something about this group of kids, with our preteen cliques and rivalries, sitting around in the dark singing a children's song, was absolutely beautiful and haunting.
It's become Leif's falling asleep song. I sing him other songs when I put him to bed, but he doesn't fall asleep until I do "I've Been Working On The Railroad."