Not being entirely happy with the result shown above, I got up early this morning in fighting mood and attacked the modified chassis with a Dremel saw to create a well that fits the underside of the grain hopper. Also note the added coupling retaining screw and washer.
That's much better. There's still a hair's-breadth of clearance between the wheels and the underside of the hopper, but it's still a fraction of a millimeter too high. I could file the hatch hinges off the top, that would just about make all the difference I think.
Or I can always run it with the top off. I wouldn't be surprised to find that this represents a genuine real-life wagon too.
That's much better. There's still a hair's-breadth of clearance between the wheels and the underside of the hopper, but it's still a fraction of a millimeter too high. I could file the hatch hinges off the top, that would just about make all the difference I think.
Or I can always run it with the top off. I wouldn't be surprised to find that this represents a genuine real-life wagon too.