A low-profile block of aluminium zipped across a short stretch of what looked like railway tracks before crashing into a tuft of sand and sending a small cloud into the clear skies of the desert north of Las Vegas.
The seconds-long demonstration on Wednesday by startup Hyperloop One marked the first public glimpse of a propulsion system that its creators hope will rocket people and cargo through tubes at the speed of sound in five years.
It took place as hundreds of journalists and investors watched from grandstands about 50 yards away after being bused to the site from a swanky casino.
Executives with the Los Angeles-based company say the system could whisk people the 560km from Los Angeles to San Francisco in 30 minutes.
They say the tubes could run underground - a safe alternative to highway crossings and inclement weather.
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The propulsion technology involves levitating pods that use electricity and magnets to move through a low-friction environment at more than 1126km/h.
