The station for the mountain railway is just a short walk from the train station. In the winter you can rent a sledge. The fair to go up to Muottas Muragl is not included in the GA train ticket and you don’t get a discount, for more information go here.
Up in Punt Muragl, the view is breath-taking, you can see both valley’s. On the right you can see St. Moritz and just to the left the frozen lakes. Where the yearly Polo tournament is held. The walking path are well prepared and marked, you can choose which way you want to go and enjoy the view.
From: Muottas Muragl train station
to: Samedan train station
Distance: ca. 12km
Walking Time: 5h
How to get there by Public Transport:
from Zurich HB: 3h 43min
from Samedan: 3h 6min
By train you will drive thru one of the Unesco World Heritage. The one you drive thru, is the Albula line it starts in Thesis and ends in St. Moritz.
On a nice day you get incredible views and you will see the alps up close. It is a cheaper alternative to the Glacier Express or the Bernina Express.
For a overview: here
more detailed information: here