Interesting, bit the hours are terrible! If you are looking to catch the tram late night on a weeknight to the Luxor from Mandalay Bay, forget it. You are better off walking or taking a taxi.
Yes, the tram is free, but is anything every free? You're in Vegas! It's very clean, safe and convenient, but if you are in a rush you are better off walking. At least the times we were taking it, it seemed to take forever. There are two trains, one that is non stop from the Excalibur to Mandalay Bay and the other that stops at Luxor.