Evening,

You can always discern the Glacier Express because it is the only train to directly connect those two points, the only one labelled FT for Fast Train, and the only one to require reservation. As you may already know you can also do the whole route reservation-free with local trains as well if you like, which is actually slightly quicker, but you’ll need to change four times (at Visp or Brig, Andermatt, Disentis and Reichenau).

Hope that helps!

Thank you for the information. I checked and looks like what you suggested is accurate. 
 

this is my first trip to Europe and the mobile app hopefully will make traveling easier  

thanks again 

Here a short article about the standard trains :)