While it appears that most (if not all) of the SD-38-2s were built for either hump or heavy duty drag freights. It might be convenient to remember that EMD (as well as the other builders) built units according to customer specs. The Mississippi Central bought 3 of the SD-28s which prior to sale to the Illinois Central did a whole lot of switching. These units were predecessors of the SD-38s. One mark of these lighter rail engines was typically a miniscule fuel tank (900 gals on the MC units if I remember rightly). And with the upgrades in rail weight and structure in the 70-80-90s wouldn't be surprised to see any size unit switching anywhere.