A great example that may surprise the unfamiliar is that of model train carriages, such as coal cars, that are capable of both receiving and dumping a load at various points on a model layout.

In Eaton, there's an experimental train car. It carries materials for energy but it isn't oil, natural gas or coal.

Epstein attempts to pop that balloon by calling the Model S a "great coal car," pointing out that about two-thirds of the world's electricity production comes from coal, natural gas and oil ...