The RhB (Rhaetian Railway / Rhätische Bahn (German) / Ferrovia Retica (Italian) / Viafier Retica (Romansh)) has the largest network of all the private railways in Switzerland. The company operates most of the railways in the south-easternmost canton of Graubünden (Italian: Grigioni, Romansh: Grischun, French/English: Grisons) since the Federal Railways SBB-CFF-FFS extend only a few kilometres over the cantonal border to the capital at Chur.
RhB serves the major tourist centre of St Moritz and Davos, and one of the lines, the Berninabahn, crosses the Bernina Pass to the Italian border and on to Tirano, where there is a link to the Italian railways.
In 2008 the Rhaetian Railway in the Albula / Bernina Landscapes was added to the list of UNESCO World Heritage Sites.
The RhB network was developed in various stages at the end of the 19th and early 20th centuries, with the result that several different electrification systems are in use, and one 12km section between Castione and Cama was completely separate from all other railways following a landslide in the mid-20th century, before later closure. All the RhB is of RailGauge|1 gauge, and is electrified:
*61km, the Bernina Bahn (Pontresina - Tirano) is electrified at 1000V.
*321km is electrified at 11kV 16.7Hz (including Chur-Arosa and the new Vereina tunnel route).
The network contains 84 tunnels (the longest being the 19.042 km (11.83 miles) Vereina tunnel, opened on 19 November 1999, and the 5.864 km (3.64 miles) Albula tunnel), and 383 bridges. The maximum gradient is 4.5%, except on the Bernina Bahn, where it is 7%.