The Brusio spiral viaduct (or Brusio circular viaduct; it, Viadotto elicoidale di Brusio, german: Kreisviadukt Brusio) is a
single-track nine-arched stone
spiral railway viaduct
A viaduct is a specific type of bridge that consists of a series of arches, piers or columns supporting a long elevated railway or road. Typically a viaduct connects two points of roughly equal elevation, allowing direct overpass across a wide v ...
on the
Bernina Railway
The Bernina Railway (german: Berninalinie; it, Linea del Bernina; rm, Lingia dal Bernina) is a single-track railway line forming part of the Rhaetian Railway (RhB). It links the spa resort of St. Moritz, in the canton of Graubünden, Switze ...
. It was opened on 1 July 1908.
A key structure of the
World Heritage Site
A World Heritage Site is a landmark or area with legal protection by an international convention administered by the United Nations Educational, Scientific and Cultural Organization (UNESCO). World Heritage Sites are designated by UNESCO for h ...
-listed Bernina Railway, it is located near
Brusio
Brusio (Lombardy, Lombard: ''Brüs'', Romansh language, Romansh ''Brüsch'') is a municipalities of Switzerland, municipality in the Bernina Region in the Cantons of Switzerland, canton of Grisons in Switzerland.
History
Brusio is first mentioned ...
, in the
Canton of
Graubünden, Switzerland, and was built to limit the railway's
gradient
In vector calculus, the gradient of a scalar-valued differentiable function of several variables is the vector field (or vector-valued function) \nabla f whose value at a point p is the "direction and rate of fastest increase". If the gradi ...
at that location within its specified maximum of 7%.
It is considered to be one of the architectural highlights of the
Rhaetian Railway
The Rhaetian Railway (german: Rhätische Bahn; it, Ferrovia retica; rm, Viafier retica), abbreviated RhB, is a Swiss transport company that owns the largest network of all private railway operators in Switzerland. Headquartered in Chur, the RhB ...
.
Location
The Brusio spiral viaduct forms part of the Bernina Railway section between
Brusio
Brusio (Lombardy, Lombard: ''Brüs'', Romansh language, Romansh ''Brüsch'') is a municipalities of Switzerland, municipality in the Bernina Region in the Cantons of Switzerland, canton of Grisons in Switzerland.
History
Brusio is first mentioned ...
and
Campascio
Brusio ( Lombard: ''Brüs'', Romansh ''Brüsch'') is a municipality in the Bernina Region in the canton of Grisons in Switzerland.
History
Brusio is first mentioned in 1106 as ''Bruse''. It was first mentioned as Brusio in 1212. Previously it ...
railway stations. It is just south of Brusio, and approximately from
St. Moritz railway station.
History
During the construction of the
Bernina Railway
The Bernina Railway (german: Berninalinie; it, Linea del Bernina; rm, Lingia dal Bernina) is a single-track railway line forming part of the Rhaetian Railway (RhB). It links the spa resort of St. Moritz, in the canton of Graubünden, Switze ...
, its engineers decided that its route and features ought to follow and adapt to the natural landscape to the maximum extent, avoiding unnecessary complexity wherever possible.
They also decided to avoid the construction of a
rack-and-pinion railway
A rack railway (also rack-and-pinion railway, cog railway, or cogwheel railway) is a steep grade railway with a toothed rack rail, usually between the running rails. The trains are fitted with one or more cog wheels or pinions that mesh with ...
due to a desire for the line to be suitable for both passenger and freight traffic; the adoption of a rack system would have made it impossible to run heavy trains, effectively preventing the line's use by freight trains. It was also desirable for the line to serve valley locations, and thus for the route to vary in height above the valley floor. It was such decisions that drove the construction of the Brusio spiral viaduct.
A spiral viaduct was required immediately south of Brusio to limit the railway's
grade
Grade most commonly refers to:
* Grade (education), a measurement of a student's performance
* Grade, the number of the year a student has reached in a given educational stage
* Grade (slope), the steepness of a slope
Grade or grading may also ref ...
to the required maximum of 7%, so that the train would not slip on the way up, or be uncontrollable on the way down. The construction of a viaduct on this site had not been originally planned for; instead, a spiral tunnel was at one point intended to be constructed; however, local geological factors discouraged the boring of such a tunnel. Therefore, the line's engineers decided to construct a 360 degree curve with a radius, rising up from the valley floor, the viaduct forms a part of that curve.
[
The spiral viaduct is long, has a horizontal radius of curvature of , a longitudinal slope of 7 percent, and is made up of nine spans, each in length. The spiral configuration maximises the rate of elevation in comparison to a conventional curve, while also avoiding the inconveniences of a switchback alternative. Wherever reasonable, local materials were sourced for its construction.]
On 1 July 1908, the viaduct was opened in conjunction with the opening of the Tirano
Tirano ( lmo, Tiràn, german: Thiran) is a town in Valtellina, located in the province of Sondrio in northern Italy. It has 9,053 inhabitants (2016) and is adjacent to the Switzerland-Italy border. The river Adda flows through the town.
Main ...
–Poschiavo
Poschiavo ( it, Poschiavo, lmo, Pusciaaf, german: Puschlav, rm, Puschlav) is a municipality in the Bernina Region in the canton of Grisons in Switzerland.
History
Poschiavo is first mentioned in 824 as ''in Postclave'' though this comes from ...
section of the Bernina Railway. In 1943, the whole of the Bernina Railway was taken over by the Rhaetian Railway
The Rhaetian Railway (german: Rhätische Bahn; it, Ferrovia retica; rm, Viafier retica), abbreviated RhB, is a Swiss transport company that owns the largest network of all private railway operators in Switzerland. Headquartered in Chur, the RhB ...
; this company continues to both own and operate services across the spiral viaduct to the present day. The services the spiral viaduct carries facilitate not only local trade purposes but tourism as well. Since 2008, the spiral viaduct, along with the rest of the route, has been recognised as a UNESCO World Heritage Site
A World Heritage Site is a landmark or area with legal protection by an international convention administered by the United Nations Educational, Scientific and Cultural Organization (UNESCO). World Heritage Sites are designated by UNESCO for h ...
.
See also
* Arch bridge
An arch bridge is a bridge with abutments at each end shaped as a curved arch. Arch bridges work by transferring the weight of the bridge and its loads partially into a horizontal thrust restrained by the abutments at either side. A viaduct ...
* Spiral (railway)
A spiral (sometimes called a spiral loop or just loop) is a technique employed by railways to ascend steep hills.
A railway spiral rises on a steady curve until it has completed a loop, passing over itself as it gains height, allowing the railw ...
* Bernina Express
The Bernina Express is a train connecting Chur (or Davos) in Switzerland to Poschiavo in Switzerland and Tirano in Italy by crossing the Swiss Engadin Alps. For most of its journey, the train also runs along the World Heritage Site known as the ...
* Rhaetian Railway
The Rhaetian Railway (german: Rhätische Bahn; it, Ferrovia retica; rm, Viafier retica), abbreviated RhB, is a Swiss transport company that owns the largest network of all private railway operators in Switzerland. Headquartered in Chur, the RhB ...
References
Citations
Bibliography
* Belloncle, Patrick. ''Le chemin de fer Rhétique, 1889-1999''. Les Editions du Cabri, Switzerland, , .
* Carter, Graeme., Colin Garratt, David Jackson, Howard Johnston, William D. Middleton and Karl Zimmermann. ''Trains: The World's Greatest Trains, Tracks and Travels''. Fog City Press, 2003. .
*
* Shales, Melissa. ''On the Rails Around the Alps''. Passport Books, 1996. .
* Widmer, Markus. ''Eisenbahnbrücken''. Transpress, Stuttgart (Germany), , .
* Wolmar, Christian. ''A Short History of Trains''. Dorling Kindersley Ltd, 2019.
External links
*
*
Webcam overlooking Brusio spiral viaduct
Video (9:56 min, 2020) of several trains traversing the Brusio spiral viaduct
{{Portal bar, Trains, Transport, Engineering, Switzerland
Viaducts in Switzerland
Rhaetian Railway bridges
Monuments and memorials in Switzerland
World Heritage Sites in Switzerland
Buildings and structures in Graubünden
Bridges completed in 1908
1908 establishments in Switzerland
20th-century architecture in Switzerland