Billionaire entrepreneur Elon Musk tweeted he would build a test track for his Hyperloop "most likely in Texas".
He provided few details about timetable or cost, although he said that he planned to use the test track to hold annual pod racer competitions.
Mr Musk envisages the system operating between cities.
There has not been much development since the founder of PayPal announced his plans in 2013.
But this week he tweeted :
And later added:
Later he told the Texas Tribune that the expected the test track would be about five miles long.Air hockey
Mr Musk, founder of Space X and chief executive of Tesla Motors, first announced plans for the Hyperloop in August 2013.
The system, he suggested, could transport passengers between Los Angeles and San Francisco in less than 30 minutes thanks to an innovative design that Musk has described as a cross between Concorde, a railgun and an air hockey table.
This would see passengers sit in cars that were then fired down a tube which had had most of its air removed. A system of magnets would accelerate and brake the capsules, and also keep them from touching the sides of the tube.
Mr Musk said that a passenger-only model would cost about $6bn and that a prototype would take three or four years to complete.
Already there is a crowd-funded California-based project - Hyperloop Transportation Technologies - that has begun thinking about how such a system could be constructed, although they have not yet produced a working prototype.
Some 100 engineers from across the US are working on the development of the system but say that they are at least 10 years away from a commercially operating Hyperloop.