landed in Siberia (perhaps the ZIL-2906). Russian inventor Alexey Burdin has come up with a screw-propulsion system "TESH-drive Transformable worms". More recently, mud farming with larger machines capable of deep profile penetration (termed MudMasters by their manufacturer) has proven to be an efficient method for high intensity tailings management. See also References Notes General references Patents A screw-propelled sleigh with refinements to keep the screw clear of ice. A single-screw, low-speed tractor mechanism. A self-propelled sleigh. A self-propelled sleigh with open screws. A self-propelled amphibious vehicle. An adaptation of an automobile to drive on ice and snow. An adaptor that can temporarily adapt an automobile to ice and snow. A hand-propelled boat with emphasis on safety. It is hard to see how these would work! An amphibious vehicle for snow, ice tundra etc. A screw-driven traction unit used to push or pull a sleigh or skiers. A device that can climb up or down steps. A tractor for swampy or rough terrain. A boat with small screws that allow it to climb onto land. A screw-driven vehicle with the option of controlling the angle of the augers and of driving them in the same direction. Chrysler Corporation design. An amphibious vehicle with non-continuous screws. An unusual arrangement with screws at 90 degrees to each other. A design for traversing the sea bed. An amphibious vehicle able to climb steeply out of the water. A peddled powered boat with emphasis on safety. External links Flixxy.com video of the Armstead machines Amphibious vehicles Off-road vehicles Vehicle technology Vehicles by type