Flood loaders have been around for a while but are still quite contemporary. There are a couple of other videos on Youtube showing the prototype and they are only couple of years old.
They really take up a small footprint, even the humongous ones in the Powder River Basin. The prototypes can be anywhere from about 100' to over 1000' feet high. Even the biggest ones would fit on an ~18x18" scale footprint. How tall you make it determines how much coal it holds, and how heavy it is.
BUT, as shown, you need a very consistent very slow speed throughout the loading for it to work. I think the prototype is between 1/4 and 1/2 MPH and has to stay consistent as the train gets heavier and heavier. Me thinks that is the real hard part.
