In 2013, Elon Musk (the billionaire behind Tesla Motors) published a white paper proposing high-altitude supersonic air travel between cities about 1500km apart. Now, reports Forbes, several companies are making it real.
Hyperloop Technologies Inc is one, aiming to "make the world smaller, cleaner and more efficient" by moving people and cargo "at speeds never thought possible". Based in Los Angeles, it is backed by investors Formation 8, Sherpa Ventures, Zhen Capital and David O. Sacks.
Its technologists are developing a high-speed cargo pod, known as the Hyperloop, which features a giant compressor fan that transfers huge volumes of air away from the nose. It carries a cargo capsule large enough to hold a standard 40-foot intermodal container. The capsule travels in a near-vacuum to reduce drag, and Hyperloop claims, should in theory accelerate from zero to 750mph (roughly 1200 km/h) in less than a minute. It then travels along a magnetic river between two (urban) points propelled by linear induction motors - rather like those currently used in Tokyo's subway.
At the Texas Transportation Forum in January 2015, Musk announced the creation of a Hyperloop test track, but did not give a date.
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Image: Hyperloop design / Tesla