Perhaps an outgrowth of the federally-initiated PRT effort of the Sixties, the leading PRT efforts of the 1990s-Early 2000s welcomed publicity, and actively disseminated the results of their work. That Raytheon was playing with millions in public funds obligated some openness, but that doesn't explain why the private Taxi 2000, and later university spinoff Ultra, was open with the public to varying degrees.
But today's would-be pod transit makers are keeping their cards close to the vest. In some cases the caginess is due to an enterprise not being on the up-and-up (e.g. Maglev Movers, IPERT1, 2, 3), but in most cases the caution arises out of business security. Four, count them, pod transit systems now exist in the world, and the competition to be the fifth might be just that tight.
The result can be 'communication' shielding a lot of mystery. Case in point: the current skyTran demonstration project in Israel. After years of work so secretive that some critics openly accused them of fraud, skyTran is now constructing a demonstration system near Tel Aviv at the campus of Israel Aerospace Industries.
Ask skyTran chief Jerry Sanders about progress and his emailed replies are enthusiastic and confident, yet only partially enlightening. He has some things to say about imminent completion of 'Phase One,' plus some inscrutable attachments. Yet his comments raise further questions; whether this is simply modern corporate communications practice is up to the audience.
A set of illustrations show a facility resembling an airport lounge or sales showroom. Given the context, could it be the Tel Aviv testing center? But no: in answer to a followup, Sanders explains --
"The illustrations show how easily skyTran infrastructure fits into the urban environment: entering buildings, lobbies, even basement level accommodations."
Maybe skyTran is excited about reinventing the elevator lobby, but seriously folks -- integrating PRT stations into new and existing buildings has been talked about for decades.
Sanders is helpful in clearing up questions about the trusses in Tel Aviv construction photos, which we thought might be station components. He explained under Phase One the guideway will be laid inside those frames, on the ground, giving engineering staff easy access. The drive unit will be tested sans passenger compartment -- that will be attached, he says by the end of the year, when the guideway will be installed on poles.
Early in 2014 we had a chance to see an official presentation containing less than vague descriptions of how skyTran planned to do levitation and propulsion. Depicted was a drive unit that reinvented conventional squirrel cage linear induction -- a motor working like a propeller, pushing against the inside of a tube instead of a flat reaction plate.
Nearly two years later and skyTran is sticking with that approach. Sanders sent us this video to show that it works.
The effect is caused by moving a magnet perpendicular to its long axis along an uncharged aluminum surface. In this video the rotor is turning at 1000 RPM.
Using the same principle to provide lift with two magnetic 'wings' reacting against vertical surfaces, the result is levitation with propulsion.
skyTran now has the hardware to create a demonstration system. It will likely work, and it won't look like past Artist Depictions, which were influenced by inventor Doug Malewicki's conceptual sketches. Gone is the super-skinny guideway, replaced with a 5.9'-wide version: either the wings won't work when close together, or all the parts won't fit inside something that narrow.
(Above) Goodbye skinny skyTran
(Below) Now: Room for four skyTran
The other big change is the vehicle, now with an ADA-friendly envelope big enough for 4 people and carryons. We can see why the wings could need to be positioned farther apart.
Whatever the reasons, the changes are good, in that they show skyTran put the engineering and society's expectations first, and didn't feel bound to the Malewicki sketches as inviolable. The result could prove to be a mechanically simpler and more reliable way to do PRT.