Detroit Airport's Express Tram

I traveled through Detroit Airport last night.  I hadn't been there in decades.  I was pleasantly surprised by the new terminal with fancy shops, cool underground walkway and much to my surprise, a fancy inside tram, in Terminal A.  Detroit's Terminal A is the second longest terminal in the world. It is nearly a mile end to end.  The tram fascinated me the moment I saw it, as it is elevated above the terminal walkways, is very fast, and operates almost silently.

Upon doing some research I found that the tram had a cruising speed of 30 mph (46.3 kph) and it levitates on a half inch of air made by 72 air pads on each train.  The trains don't have motors inside but instead are pulled on cables at the end of the concourse. This system works like an elevator and was even designed and built by Otis Elevator Company in Connecticut. The air cushion that the train rides on minimizes friction because there is no rubbing of parts and it also keeps vibrations and noise in the terminal down.  This means the tram is very efficient, as the mechanical (kinetic) energy from the motors can get transfered to the kinetic energy of the train moving, and little energy gets lost in the form of sound energy (noise), friction and heat.  Even the fact that the train doesn't vibrate the building means the energy stays as kinetic energy in the train, rather than losing kinetic energy by transfering it to the building.