In Wisconsin, GB&W moved sand and gravel in open twin hoppers from online pits to a concrete batch plant in Green Bay well into the 1960s.  WSOR still does this today, moving both sand and gravel in open hoppers (until a couple years ago in railroad-owned conversions of 1958 cu ft LO's - similar to the new Bowser kit) from a pit north of Janesville to concrete plants in Burke, Middleton, and Monroe.

Andy L.
Madison WI