The containerization referred to by OPB was called Flexivan, and was championed by Al Perlman @ the NYC. The service was not universally accepted by fiscally conservative RR's in the U.S.; only a few progressive ones were willing to spend precious capital on the specialized flatcars required for the service. A few other RR's, notably Espee, invested in another design known as Clejan. BTW, those flatcar - mounted turntables were not much fun to turn in Toledo in January, and invariably a terminal receiving 30 Flexivans would only have 20 wheel bogies on hand...