Ore Jennies. Well Cars. Flatcars. The Caboose. Autoracks. B&O's "Wagontop" Cars. Perfectrding to Mike Schafer's book, " Freight Train Cars ," the use of springs was one of the earliest known freight car improvements. By the 1830's the first four-wheel truck, one attached at each end, was employed on the B&O. The original inventor of the device has