It's interesting to think back to a time when nearly everything moved in box cars, even automobiles. There was a lot of resistance to all those new-fangled special-purpose cars as they were being developed. Too much empty back-hauling to suit thrifty/skin-flint operating types. 
I went with my friend Jim one time in his truck (Kenworth COE pulling a 53ft covered-wagon). We left Youngstown in the afternoon with a load of dashboards (cubed-out at only 11,000#) bound for Huntsville the next AM. We left Huntsville and dead-headed a short distance to an empty barrel depot someplace in Western Tennessee where we loaded (that's right, "we" as in Jim&I) empty stinky 55gal barrels. Drove East across the mountains into NC where we dropped the load of barrels somewhere near Charlotte (they unloaded with a fork-lift because we had put down pallets before hand-loading loading those barrels). We then dead-headed over to a paper mill on the coast just North of Charleston where they loaded on two huge rolls of paper. They didn't load them just right so Jim had to slide both the Fifth-Wheel and the trailer tandem to get the axle-loadings legal and then away we went to a big warehouse around state College, Pa. Then we dead-headed home, a couple hundred miles. Railroad box cars and truck covered-wagons definitely have their advantages.
I think one reason many switching-pike enthusiasts back-date is to operate in the age of nearly universal use of box cars because an elaborate switch-list serving several diverse industries can be implemented using a relatively small yard full of box cars.
