FOR years Elon Musk, a South African-born tech entrepreneur, has been telling anyone who will listen that the future of travel is the hyperloop. (Although he thinks it might also be driverless cars. Or perhaps affordable space travel.) Dubai may be about to test the limits of Mr Musk’s imagination.

The hyperloop is a train that moves along a tube that is kept at a thousandth of the normal atmospheric pressure at sea level. Because air resistance is one of the biggest obstacles to high-speed travel, all but eliminating it means that hair-raising velocity becomes possible. The proposed technology could shunt passengers along tunnels at perhaps 745mph, which is faster than a jet plane.