Advocates of Evacuated Tube Transport (ETT) claim it is silent, cheaper than planes, trains or cars and faster than jets.
The basic plan is, well, as old as the enabling patent, US Patent 5950543, whose description is quite thorough. Issued in 1999, there remain seven years on the term of the patent, which is assigned to ET3.com, Inc., a licensing organization that hopes to head an alliance of players to fund and construct demonstration facilities.
The short version of the ETT story is as follows: put a superconducting maglev train in evacuated tubes, then accelerate using linear electric motors until the design velocity is attained. As the motors are integrated into the evacuated tubes, the conveyance capsules which travel in the tube need have no moving or electrically activated parts - passive superconductors allow the capsules to float in the tube, while eddy currents induced in conducting materials drive the capsules. Efficiency of such a system would be high, as the electric energy required to accelerate a capsule could largely be recaptured as it slows. […]