The trams are not public transportation. They are privately owned by the MGM-Mirage corporation to shuttle people between their properties and encourage them not to wander off to one of their rival casinos. MGM-Mirage is the top grossing company in Las Vegas at about $21million/day. It is two miles from the northern edge of the Bellagio to the southern edge of Mandalay Bay. The tram is 1/2 mile.
When you are heading south from the Excalibur you must go all the way to the Mandalay Bay, since the corporation wants you to see their expensive hotel. On the return trip, you can stop at the Luxor.
When they complete the City Center project next year, they will add a second tram connecting the Bellagio, City Center, and Monte Carlo. Since it is part of the design of the building, the three stations will be more centrally located.
The third tram between the Mirage and Treasure Island is very short and doesn't run as often. It is hardly worth the trouble of waiting in line.
The technology is essentially a modified ski-lift that is pulling rubber wheeled vehicles.