Castielertobel Viaduct

46.835212879.5934248830Koordinaten: 46 ° 50 ' 6.8 "N, 9 ° 35' 36.3 " E; CH1903: 764369/189375

Castielertobelbach

The Castielertobel Viaduct is a single-track railway bridge on the Rhaetian Railway in the field of community Arosa in Schanfigg / Canton of Graubünden in Switzerland. He was up to his static -induced remodeling in 1942, the largest stone arch bridge in the Arosa train.

Location

The building is part of the narrow gauge railway line from Chur to Arosa is located between Calfreisen and Castiel. It is after Langwieser viaduct and the Gründjitobel Viaduct is the third largest bridge in the Arosa line. The viaduct carries the railway line about 330 meters below the bridge of the Schanfiggerstrasse about the Castielertobel, a wild and deep gorge of Bündnerschiefer. Similar to the Landwasserviadukt the bridge leads directly into a tunnel; Here emerges the train in the 249 m long, S- shaped bear trap tunnel.

Architectural History

Because of the difficult geological conditions in Schanfigg had to be created for the privately built 1912-1914 Chur- Arosa line a total of 19 tunnels and 52 bridges. Like most bridges, the Castielertobel Viaduct was created in the classical manner mainly of stone, the particular location of the site was responsible for ensuring that you used stamped concrete for the core of the pillar. When spectacular and topographically extremely difficult crash Castielertobels - the so-called bear trap, which was still almost unknown despite their relative proximity to the main road in front of the building - have had to make do when unplugging the line of fire and smoke signals engineers. During construction of the bridge 's access Sassal out via Calfreisertobel over the already built Trassee on makeshift rails was designed. Horses pulled the required material on trolleys to the site. The bear trap tunnel was taken on the uphill side of Castieler Eichwald from attack. He was already hit, as the two pillars of the viaduct were still under construction. Despite the difficult situation of the construction progress was even surprisingly easily: While in April 1913 only the main pillar was founded, was in November of the same year, the entire viaduct to the cover done there. In contrast, threatened at the upper portal of the bear trap tunnel a rock slump the passage just to lock in the moment when the machine transport should start at the power plant Lüen.

Stabilization measures and remodeling in 1942

The building soon proved to be very unfavorable, with the result that the 53 m high main pillars slipped every year by about 6 mm to Plessur. This led, after some time considerable vault deformations with it. After long observations and in-depth investigations therefore in 1931 a first reconstruction of the viaduct was tackled. The valley-side abutment was this venture formed with a bell-shaped concrete block. This was covered with Hunzikersteinen reinforced with railroad tracks and had a diameter of 14 m and a height of 9 m. The new foundation base was 21 m below the previous line terrain. This work was carried out by the company B. & C. Caprez.

It soon turned out that this measure was not sufficient. 1942 was therefore a complete reconstruction of the entire bridge structure. All three stone masonry arch were removed and replaced with iron beams to avoid slippages and against related strains no longer be vulnerable. By lying down fish-belly support ( " LOWER " ) was a maximum of stability can be achieved. Chief Engineer Hans Conrad headed this sensational reconstruction without the railway operation had to be interrupted. A special construction allows since balancing these with modern means unstoppable slip motion. Regularly both pillars are checked to detect irregularities immediately. The attached control device makes it possible to register even the slightest shifts. In addition caused a suspended on wire ropes rail load of 7 tons for a pulling action of 50 tonnes on the pillar head and pulled it in the direction of Chur. In 2006, the building has undergone extensive renovations again, said rail load was replaced by a technically sophisticated train system.

Gallery

Viaduct seen from the Schanfiggerstrasse

Steel beam to the tunnel with markings of wall cracks

Pier head with adjustable road camps

Measuring device to the road storage

Swell

• Hans -Bernhard Schönborn, the Rhaetian Railway. Past and present. Geramond, Munich 2009, ISBN 978-3-7654-7162-9, pp. 116, 118, 124, 125
• Hans Danuser: Arosa - as it was then ( 1907-1928 ). Volume 2 Eigenverlag Danuser, Arosa 1998, pp. 89-92.
• Hans Hofmann: Chur- Arosa, from the construction and operation of the railway. 2nd edition. Calanda published by H. Hofmann, Chur 1993, ISBN 3-905260-11-5, pp. 43-47, 65, 76-79.
• Beat Moser: The RhB. Part 3: St. Moritz -Samedan - Zernez - Scuol- Scuol, Pontresina and Samedan - Chur- Arosa. The electric locomotives of the RhB. Hermann Merker Verlag GmbH, Fürstenfeldbruck 1998, ISBN 3-89610-038-6, ( Railway Journal 1998, 4, Special Issue ), p 74