Summary

1. Introduction
The Rhaetian Railway (RhB) is the actual "State Railway" of Grisons, the largest Swiss Canton, and serves the most important valley communities. The RhB came into existence from a private initiative, after the decision for the North-South railway link through the Alps was made in favour of the Gotthard route in the 19th century and Grisons was left out in the cold with the Spluegen Project. From the year 1889 a metre gauge network developed which has an operating length of 200 km today. The latest line to be opened was the Vereina line in 1999 with the 19 km long Vereina tunnel. A classic and well-known mountain line is the Albula line from Chur to St.Moritz in Engadine (Glacier Express). However, it is the continuation of the Bernina line from Engadine over the Bernina pass through Poschiavo to Tirano which has a particularly extreme line route and is the highest open railway crossing through the Alps.

Bernina line: 61 km total length
Track gauge: 1000 mm
Max. gradient: 70 ‰ over 27 km length (adhesion)
Min. curve radii: 45 m (terminal loops/hairpin bends)
Axle load: 12.5 t
Highest point: 2,253 m above sea level (Bernina pass)
Lowest point: 429 m above sea level (Tirano, Italy)

2. Demands on the track
The winding and steep gradient lines set a great challenge on the track. The special climatic conditions also have an influence on the track. Appropriate demands are placed on the track geometry and bearing stability for the durability. The designs usual today, such as long welded track, are gradually being introduced for the tightest curves. Technical aspects of running (rolling contact/contact geometry) influence the wearing behaviour on rail and wheelset and must be taken into consideration.

3. Maintenance strategy
Mechanised track maintenance and track renewal have been strived for and achieved to a great extent. Track maintenance machines of appropriate design are required for work in the tight curves and to overcome the steep adhesion slopes. Attention should also be paid to a well co-ordinated wheel flange/rail lubrication. Special constructional features and equipment for snow clearing are necessary to keep the track over the Bernina pass open in winter.

4. Prospects
Even on a mountain railway with some extremely difficult line conditions, it must be possible to achieve a high cost-efficiency by using up-to-date and proven technologies for maintenance and renewal of the track.