The Albula railway line is a single track metre gauge railway line forming part of the core network of the Rhaetian Railway (RhB), in the canton of Graubünden, Switzerland. It links Thusis on the Hinterrhein at 697 m (2,287 ft) and Filisur at 1,080 m (3,540 ft) with the spa resort of St. Moritz in Engadine at 1,774 m (5,820 ft).

The Rhaetian Railway, abbreviated RhB, is a Swiss transport company that owns the largest network of all private railway operators in Switzerland. Headquartered in Chur, the RhB operates all the railway lines of the Swiss canton of Grisons, except for the line from Sargans to the cantonal capital, Chur, which are operated by Swiss Federal Railways (SBB CFF FFS), as well as the line from Disentis/Mustér to the Oberalp Pass and further on to Andermatt, Uri, which is operated by Matterhorn Gotthard Bahn (MGB). Inaugurated in 1888 and expanded from 1896 onwards in various sections, the RhB network is located almost entirely within Grisons, with one station across the Italian border at Tirano.