the transition speed, the magnetic drag decreases with speed. For example, at the lift to drag ratio is 200:1, far higher than any aircraft but much lower than classic steel on steel rail which reaches 1000:1 (rolling resistance). This occurs because the inductive impedance increases proportionately with speed which compensates for the faster rate of change of the field seen by the coils, thus giving a constant current flow and power consumption for the levitation. The Inductrack II variation uses two Halbach arrays, one above and one below the track, to double the magnetic field without substantially increasing the weight or area of the arrays, while also reducing drag at low speeds. Several maglev railroad proposals are based upon Inductrack technology. The U.S. National Aeronautics and Space Administration (NASA) is also considering Inductrack technology for launching space planes. General Atomics is developing Inductrack technology in cooperation with multiple research partners. Evolution of InducTrack Depending the application, lift to drag ratio at low speed or higher speed are favored. The three variation of the Inductrack are designed for different purposes. The Inductrack I was designed for high speed trains. The lift to drag ratio is lowering while speed increase. The Inductrack II have more capabilities of levitation at relatively low speed for use in individual (PRT) or urban transport and use a cantilevered track. The InducTrack III is designed for high load and cargo with track only partly cantilevered to sustain high loads. Damping There is no active damping and the damping is only provided by the geometry of the track. Tests have shown that low frequency oscillations (1Hz) occur and a US patent for mechanically damping the track itself (on Inductrack II) was issued (7478598). The track is cut in segments and each segment is mechanically dampened. Applications Hyperloop Transportation Technologies announced in March of 2016 that they would be using passive Inductrack systems for their titular Hyperloop. References External links General Atomics, Urban Maglev(Retrieved 28 May 2013) Lawrence Livermore National Laboratories: Richard Post contributions S&TR article on Inductrack Media articles and technical reports on Inductrack, 1998 to 2005 Electric Cargo Conveyor System with Inductrack, General Atomics, Final Report, October 2006 The International Maglevboard The Inductrack Maglev system, Presentation on 10 Oct 2005 Patents Maglev Rail technologies