What are we looking at here? It seems obvious to me that it was designed to clear the track, but of what? And why? I worked for a sand and gravel company, loading sand into RR cars, but never needed anything like that.
I would guess that it's to clear spilled sand & gravel, especially from bottom-leaking cars (rolling stock). My Dad managed an aggregate washing/drying company (foundry quality sand) and that stuff got everywhere.