the train

We are taking the TA on the Royal Oct 21 but flying to Madrid first and will be taking the train to Barcelona but confused with the class on the train. They have Economy which costs the most, Premium which is in the middle and comfort is the least...Anyone have a idea on which one of these makes the most sense as my group is very confused

First, I would start with some research on the Spain board, here:

http://boards.cruisecritic.com/forumdisplay.php?f=596

as this has nothing to do with Princess, and you will find many experts over there. In fact, it is likely the Mods will move it there.

What site are you using to get this very confusing info? On the Renfe site, the official Spain train service, I am seeing Tourist, Tourist Plus and Preferential. I would book on the Renfe site and avoid sites like raileurope.