That looks an awful lot like one of these, which is a production cargo trike:
I suppose it could be homemade, but that looks like the standard Worksman front hubs there.
And technically, it's not "alt" because it's a factory product.
(Actually, looking at it, it's a different model if it's a Worksman. They make one with wide platform above the wheels, and one with narrower platform between the wheels- go to
www.worksmancycles.com, click on "industrial" then "tricycles" to find these.)