After a hard push up Mullan Pass, A helper set with four SD70ACe's and a tag-along SD45 roll light down the grade at Austin Montana. Before the rehabilitation of Mullan Tunnel, the helper locomotives (especially the ones on the east end) would get filthy after only one trip through the tunnel. It looks like some poor crew member got some of that filth on their clothes when they walked down the flank of the first SD70ACe.