On the Saar you can see a Lastschiff (barge). It is pulled by horses along the river on the Beurig side using Leinen (long ropes). The ropes can just be made out, and the men who guided the horses on the towpath - the Halfen - are invisible. It is my guess that they are there but that they look like a cluster of trees. The artist was interested in the castle, the city of Saarburg, and the river itself. He gave short shrift to the Halfen, as was all too often the way they were also treated in real life.
However, a postcard from the collection of H.D. Jung of Saarburg shows a picture of one of the Halfen and the strong horses that pulled the barge's load against the tide.