CSX Helpers In Baltimore, in 2007
CSX uses helpers in Baltimore on heavy trains heading through the, surprisingly steep, grade through the Howard St Tunnel. I caught a set of them at work back in 2007 at St. Denis MD.
The helpers are usually tied on west of town, often on the Old Mainline at Avalon, and are help the train east, through town, over to the Bayview Yard area.