NoviceTravel For the Bernina Express I suggest to take normal trains, no reservation is required, but you have to change more frequently:
Example of actual timetable. You have also other trains, check the timetable before you travel:
St. Moritz departure 08:48
Tirano 11:00
From Tirano to Lucerne with normal trains:
Tirano departure 13:41
Lucerne 20:25
From Tirano to Lucerne with the Bernina Express until Chur (seat reservations are mandatory for panoramic cars):
Tirano departure 14:24
Lucerne 20:51
For the Glacier Express seat reservations are mandatory, but you could also take local trains without reservations. The rolling stock of the local trains is often old and not comfortable, but you can open the windows. It is appreciated to take pictures.