The Chur–Arosa railway line, also called the Arosabahn, Arosalinie, Aroserbahn or Aroserlinie (all meaning Arosa railway or line), is a Swiss metre-gauge railway line, which is owned and operated by the Rhaetian Railway (; RhB). It was built in 1914 by the Chur-Arosa-Bahn (; ChA) to connect the Grisons capital, Chur, with the spa town of Arosa. Since 1942, it has been integrated into the network of the Rhaetian Railway. The name of the former company is still used as a name for the line.
Route description
The branch line starts on the forecourt of Chur station, where the trains to Arosa use tracks 1 and 2, each adjoining an outside platform. A rail track connects to the Landquart–Thusis railway, although this is only used for the movement of rolling stock to and from the main Landquart workshop.
The railway traverses the urban area of Chur, initially on two tracks. This section is similar to a tramway and consists of grooved rails. At one point the line runs across a roundabout. After about , the line becomes single-track before crossing Grabenstrasse. Soon after, it reaches the right bank of the Plessur and a little later Chur Altstadt near the historic centre, which is now the only station on the line classified as a halt. Shortly before leaving Chur, the Sand depot and workshop is located on the left in the suburb of Sand. Today, it is used to store the vehicles of a track construction company, but part of it can still be used as a crossing loop.
About later, the line leaves the roadway. For a few hundred metres, it now runs to the right of the considerably narrower road on Vignoles rails, until the line reaches the former halt of Chur-Sassal, which was abandoned in 2001. Immediately afterwards, the line crosses the Churs city limits from which the railway runs completely independently of the road as a mountain railway up the Schanfigg valley.
The rest of the line contains many civil engineering structures, including a total of 41 bridges, 19 tunnels and 12 avalanche-protection galleries. The largest structures are the Langwieser Viaduct, the Gründjitobel Viaduct—both in the territory of the former municipality of Langwies—and the Castielertobel Viaduct between Calfreisen and Castiel. The longest tunnel is the Lüener Rüfe tunnel.
Over its whole length, the line climbs a total of in elevation and crosses the Plessur once and the Schanfiggerstrasse (Schanfigg road) three times. The five intermediate stations of Lüen-Castiel, St. Peter-Molinis, Peist, Langwies and Litzirüti are served before the line reaches the terminus of Arosa on the Obersee (upper lake), from Chur. There are two additional crossing loops at Untersax and Haspelgrube.
Operations The trains take just over an hour to complete the journey. With the exception of Litzirüti and Langwies, all the intermediate stations are request stops. A Regio service runs hourly, requiring three sets. They are scheduled to cross in Lüen-Castiel and Litzirüti.
In addition to the Regio trains, two additional RegioExpress pairs, which do not serve all intermediate stops, run in the winter season. Two pairs of regional services run in the summer season; these include open summer cars when the weather is good.
Train paths are allocated for freight traffic on the line, but freight trains operate only when there is a substantial need. Normally, freight wagons are attached to passenger trains.
Passenger traffic has amounted to around 400,000 trips per year in recent years. The Arosa Railway carries more than 50,000 tonnes of freight a year—mainly in the form of wood, gravel, sand and cement.
History Projects and preparatory work The first proposals for a railway from Chur to Arosa originated around the turn of the twentieth century, when it was realised that the Schanfiggerstrasse, which was completed in 1890, would not be able to cope with the traffic bound to the rapidly expanding spa of Arosa. Local spa doctor Carl Rüedi was the first to apply for a concession to build a railway line. A meeting was held in St. Peter with the Schanfigg stakeholders on 9 February 1901. It was planned to run the line along the cantonal road after it was widened with some sections on separate track through tunnels in difficult places. The terminal station would have been built on the Hubelwiese at the Hotel Hof Arosa. After the unexpected death of Rüedi in June 1901, his concession lapsed and his plans were no longer pursued.
The Chur engineer Robert Wildberger and his colleague Englert applied for a concession for the construction of an electric railway to Arosa in January 1903. Their application competed with numerous other applications filed in the meantime. The most notable counter-proposal came from the Zurich-based firm of Müller, Zeerleder, Gobat & Thomann, which later built the Gründjitobel Viaduct. It put forward three different options, with the first involving a line running on the left side of the Plessur. The second option, with a total length of , would have run via Passugg, Tschiertschen and Litzirüti to Arosa. The third option would have essentially followed the Schanfiggerstrasse on a route. The latter two options provided for rack railways to overcome the slope, which was expressly not recommended by the chief engineer Moser of Zurich, who had been commissioned by the municipality of Arosa.
In view of the differing interests of the valley communities, the previous applicants for a concession joined together in March 1905 to prepare a joint study with three different options. All three proposals began at the Chur station forecourt, headed west and crossed the Plessur near the Welschdörfli district, ran under the Rosenhügel through a -long tunnel and had their first stop at Bodmergut. Finally, at the end of October 1907, there was a modified project which, although later realised, was initially rejected by an Arosa town meeting. The location of the Arosa terminal station was particularly controversial. As a result, the Arosa municipality first decided to examine more closely another proposal from the Churwalden line (Churwaldnerlinie) company for a line from Chur via Passugg, Malix and Parpan to Arosa with a possible, later, connection to Lenzerheide. The core of this project was a tunnel connection under the Urdenfürggli and the Hörnli mountains to the Wasserboden lake at an altitude of . The terminus would have been located in Innerarosa near the Bergkirchli (church). The application for a concession was lodged on 15 October 1908.
It was followed by a protracted competition between the Wildberger & Co. project, which was revised again and favoured by the Schanfigg valley communities, and the proposal of Ahlsfeld & Spyri, which initially also found the support of the city of Chur. For a short time, another project via Tschiertschen was also discussed. After a conference to determine a way forward in December 1909, the Chur city council supported the project of Wildberger, which also caused a change in opinion in Arosa and led to a withdrawal of the Churwalden line's application for a concession. Nevertheless, an engineer from Chur, Versell, proposed a new, option, the so-called Lenzerheidebahn via Malix, Praden, Tschiertschen and under the Ochsenalp to the Obersee. Although this proposal enjoyed a degree of support in Arosa, it focused from then on the financing of the Wildberger proposal, which provided for a pure adhesion railway with a maximum of 6.0% grade. In March 1910, negotiations were conducted on the location of Arosa station and the route was optimised. Since the rolling stock of the RhB would be able to run on the line, the minimum radius of curvature was set at .
Foundation of the ChA and construction Even before finance for the railway was definitively secured, the ChA was provisionally constituted on 15 July 1911 and formally established in Chur with a share capital of CHF 7.6 million at its general meeting on 4 July 1912. The canton of Grisons was a majority shareholder from the beginning. Gustav Bener, who had been commissioned as chief engineer, and the Wildberger company resolved outstanding issues and presented plans to the Grisons government for approval on 4 March 1912. Construction began on 1 August 1912 under the direction of Bener and his deputy Hans Studer, the builder of the Wiesen Viaduct. Since the city of Chur was planning to build a tram line at the same time, it suggested that the route from Arosa to Sassal be routed through the city. With the elimination of the Rosenhügelel tunnel and the two bridges over the Plessur, the ChA reduced construction costs by approximately CHF 150,000. The track was divided into four lots, which employed a total of about 1,000 workers. The unstable terrain made site management difficult, causing the original opening date of 15 November 1914 to be postponed.
In November 1913, a retaining wall collapsed at the Dorfbach bridge; the existing steel girder bridge was being extended with the addition of three segments, which as a result lay on a curve with a radius of . In February 1914, after the collapse of a retaining wall, of fill along with the track collapsed. In March 1914, the tracks were dislodged at the east portal of the Sassal III tunnel. In April 1914, the dome of the Nesslaries tunnel deformed and the vault in the Bärenfalle tunnel collapsed. The ground had to be stabilised and drained between km 4.7 and 5. In addition, the vault of the Spundscha tunnel was so deformed that a bypass tunnel had to be built. This tunnel work started on 9 April 1914 and took only five months. During this time, the trains ran over a wooden bypass bridge, which could support an axle load of 12 tonnes. The construction of the Lüen power plant, which was intended to supply both the railway line and the city of Chur with electricity, was not allowed to fall behind, unlike the other works. In addition to the difficult terrain, preparations for the general mobilisation at the beginning of the First World War also caused serious problems, as various construction workers and engineers were drafted for military service. In particular this affected Hans Studer, who had to resign from his post as deputy chief engineer.
Despite all difficulties, the line was finally opened on 12 December 1914 after only two years of construction. With construction costs of CHF 402,700 per kilometer, the Chur–Arosa line was the most expensive on the Rhaetian Railway network.
Operation and maintenance 1914–1988 / merger with the RhB in 1942 The journey from Chur to Arosa initially took between 80 and 85 minutes. The ChA used a different electrification system for its blue and white rolling stock than the neighbouring Rhaetian Railway, namely the rare voltage of 2400 volts DC. At the beginning of the 1930s, the heavily worn rails were replaced and extended the sidings. A concrete rockfall shelter was built between the Sassal I and II tunnels in 1931.