A small enhancement to one of my Accucraft wagons; the flat wagon (single plank) had no load and I was lucky to find a generator engine of the about thee right scale at a recent Toy&Train fair.
I decided to make the load removable, so it was mounted on a card base cut to fit on the wagon...
I gave the card base a coat of brown and a wash of dark grey, then stuck on the generator. The load in place on the wagon