Tracked Hovercraft was an experimental high speed train developed in the United Kingdom during the 1960s. It combined two British inventions, the hovercraft and linear induction motor, in an effort to produce a train system that would provide inter-city service with lowered capital costs compared to other high-speed solutions. Substantially similar to the French Aérotrain and other hovertrain systems of the 1960s, Tracked Hovercraft suffered a similar fate to these projects when it was cancelled as a part of wide budget cuts in 1973. History Genesis at Hovercraft Development It was noticed early on in the development of the hovercraft that the energy needed to lift a vehicle was directly related to the smoothness of the surface on which it travelled. This was not entirely surprising; the air trapped under the hovercraft will remain there except where it leaks out where the lifting surface contacts the ground — if this interface is smooth, the amount of leaked air will be low. This is the purpose of the skirt found on most hovercraft; it allows the fuselage to be some distance from the ground while keeping the air gap as small as possible. The surprising discovery was that the amount of energy needed to move a given vehicle using hover technology could be lower than the same vehicle on steel wheels, at least at high speeds. Over , conventional trains suffered from a problem known as hunting oscillation that forces the flanges on the sides of the wheels to hit the rail with increasing frequency, dramatically increasing rolling resistance. Although the energy needed to keep a hovercraft in motion also increased with speed, this increase was slower than the sudden (and sometimes catastrophic) increase due to hunting. That implied that for travel above some critical speed, a hovercraft could be more efficient than a wheeled vehicle running on the same route. Better yet, this vehicle would also retain all of the positive qualities of a hovercraft. Small imperfections in the surface would have no effect on the ride quality, and the complexity of the suspension system could be greatly reduced. Additionally, since the load is spread out over the surface of the lifting pads, the pressure on the running surface is greatly reduced — about the pressure of a train wheel, about of the pressure of a rubber tyre on a road. These two properties meant that the running surface could