Feb 10, 2015 - 12:16 PM
Thanks for that, now I see what confuses you. If you look at the details of those connections, you will see that it's just the last 10 minutes of the trip, between Pontresina and St. Moritz, which is a bus service. The timetable suggests that because it takes a while before the next train to St. Moritz departs, so it suggests the bus to get there quicker. You can wait for the train too if you prefer that, but there's no major difference as it's just a 10 minute ride. If you click "advanced search" in the timetable, you can exclude buses as a mode of transport if you like.
The Bernina Express is more luxurious than the regular trains, but both are fine.
I hope this clarifies the bus mystery!