The High Tops are on the DLS, but I dont think there are any NS paint jobs. They are used to haul wood chips. Wood chips are lighter the coal, to make up for this, more car is needed to hold the same weight.
As for the other car's, those are Bethgons. They are used mostly to haul coal are ar typicality unit trains. The individual cars have a rotatory coupler on one end, marked by painted one end of the car a different color. This lets the cars go thought a rotatory dumper as a whole train. Its one of the only ways to unload Bethgons as the bottom dose not open on them.