maybe that bulk tipper was a walking floor trailer delivering palletised goods, did it have barn doors swinging to the sides ■■
get to location, dismount moffet from trailer, open barn doors, start the floor moving bringing pallets to the rear
of the trailer, to be offloaded by the moffet.
Scooby - appeared to be a regular old tipper trailer to me but I could be mistaken. That idea with the walking for does sound like an easy life though.
Edited to erase the idiotic autocorrected nonsense my phone came out with.