Walter Grotte, 81, of Finley, North Dakota, has been moving silos for nearly 50 years. In 1981 — 40 years ago — as a way to make his farm cash-flow through the farm credit crisis, he invented and built a 30-ton silo mover for the iconic but pricey blue Harvestore silos. His Mighty Mover debuted to great acclaim at Big Iron in 1984. Just ahead of Big Iron in West Fargo, Grotte, 81, is still using the machine, in a partnership with his grandson, Max Grotte, of Hope, North Dakota.