My TOFCEE yard shows a typical configuration early in its history, with converted standard flat cars, truck trailers right off the road, and loading via ramps at the end of a track stub. In short order, this popular service evolved through specially-built flats and truck trailers with removable underframes, and crane loading and unloading, up to today's depressed-center, double stacked intermodal trains, as shown below.
See my Finished Area Photos page for more pics and info on my model of this area.