The Monongahela is still very much a working river, and barge trains like this are a common sight. This one is empty and going upstream. Somewhere up there these barges will be filled with coal and come back downstream with their loads.
The boat that pushes the barges from behind is called, defying common sense, a towboat (corrected from “tug,” thanks to the helpful comment of a kind reader). Working on the barge trains is a dangerous business, but river culture has its own romance, with strong traditions passed on through the generations that most of us who spend our days on dry land know nothing about.