Albula Tunnel
Overhead catenary ,11 kV AC 16 2/3 Hz | |
Highest elevation | 1,820 m (5,970 ft) above sea level |
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The Albula Tunnel is the centrepiece of the
The northern portal of the tunnel is at
Due to the threat of rockfalls and general deterioration over time, it was planned for the original tunnel to have been renovated during the 2020s.[citation needed] But in 2010, the Rhaetian Railway announced that it had identified the construction of a second tunnel alongside the first as its preferred option, with one of several reasons being a relatively minor difference in cost.[4] Costed at around CHF 244 million, construction commenced during 2014. In comparison to the original Albula Tunnel, the new bore is considerably larger due to newer operational and safety standards. The second tunnel is set to be opened to traffic in 2024, with completion of the project including refurbishment of the original tunnel by 2025. Once completed, around 15,000 trains are predicted to use the tunnel each year; it has been built to allow for a maximum speed of 120 km/h (75 mph).
History
Construction
The Albula Tunnel is a major feature of the Rhaetian Railway (RhB), an extensive metre-gauge network in the southeast of Switzerland that was launched during 1889.[3] The railway's management had placed a significant emphasis on the line being attractive to the growing tourism market, thus the line traverses the northern valleys in a deliberately spectacular manner. The highest point of the line, being roughly 1,800 metres above sea level, is where the Albula tunnel was constructed.[3]
The construction effort was impacted by multiple unusual problems. The cold, 6 °C (42.8 °F), water outflows transformed the already fractured rock into a pulpy mass, regularly clogging up the shell of the northern tunnel lead (or
From 1 April 1901, the Rhaetian Railway took the construction work into its own hands. With the use of a bonus system, it was able to regain part of the lost time. At 03:00 hours on 29 May 1902, the breakthrough of the two tunnel leads was achieved, at a point 3,030.5 m (9,943 ft) from the north portal, and 2,835 m (9,301 ft), from the south portal.
The finished tunnel had a length of 5,864 metres and contained a single track.
During 1903, Albula Tunnel was opened to traffic.
By 2006, inspections of the tunnel determined its condition to have degraded to the point where significant renovations were required. By this time, around 7.4 million passengers, including 2.3 million
While a second tunnel was constructed during the 2010s, the original Albula Tunnel has been retained.[3] A total of 12 cross passages are to be excavated between the two tunnels, which shall enable personnel to travel between either bore, useful during emergency situations and routine maintenance activities alike.[7] Following the completion of the second tunnel, the older tunnel has been scheduled to be temporarily closed to rail traffic while extensive repair works are carried out; this activity is to be largely focused on the stabilisation of its walls and roof.[3][8]
Second tunnel
This article needs to be updated.(October 2019) |
Due to the declining condition of the original tunnel, the prospects for the construction of a brand new tunnel alongside the old was evaluated alongside other options; Studies determined that the total cost of such a tunnel would be around CHF 244 million.[3] During 2010, the RHB announced that the building of a new tunnel had been identified as the optimal solution; detailed planning work commenced that same year.[3] There were several advantages presented by this option. Most obviously, the old tunnel would be able to remain in use throughout the construction of the new tunnel, thus avoiding a lengthy closure of the line for its renovation. The presence of the existing tunnel also enabled it to act as a rescue bore for the new tunnel if ever required to do so. During December 2012, RhB handed over the plans for approval to the Federal Office of Transport.[citation needed] Close cooperation between RhB and authorities is necessary, particularly due to the location being an UNESCO-recognised World Heritage Site.[9]
During 2014, construction of the second tunnel formally commenced.[3] In comparison to the original Albula Tunnel, the new bore is considerably large in terms of both width and height, which is primarily a result of the need to implement various newer operating standards and a greater consideration on its safety.[3] The larger dimensions of the tunnel enables it to accommodate walkways throughout its length, as well as facilitating ideal clearances for the OLE fixtures. During its construction, the bore was sufficiently large and flat enough for road vehicles to directly reach the rock face, enabling conventional machinery to be brought in.[3] Despite its increased width, the new tunnel is actually slightly shorter than the original bore, being roughly 5,860 metres in length.[3]
The tunnelling method was in line with conventional practices of the time.
Whilst the
As a result of the heavy snowfall typically present in the Swiss Alps during the winter months, which caused unavoidable accessibility disruptions to the tunnel site, all construction work was suspended between mid-December and the end of February. Outside of this seasonal shutdown, the site was worked 24 hours per day each day via shift working.[3] According to Rail Engineer, an average distance of 6.5 metres would be driven during a single day. However, due to geological complications present at one part of the bore, the rate of progress was decreased to only around 0.7 metres per day.[3] Boring shall involve a total of roughly 244,000 cubic metres of rock being excavated.[3]
The construction phase has been forecast to last 8.5 years; by August 2018, the tunnel's completion was expected sometime in 2022.[3] On 2 October 2018, breakthrough between the two ends of the new bore occurred, a key milestone in the construction programme.[10] In addition to the new tunnel itself, both Spinas and Preda stations on either side of the tunnel shall be modified.[10] Once completed, around 15,000 trains are predicted to traverse the tunnel each year; it has been built to allow for a maximum speed of 120 km/h.[3]
Sources and references
Citations
- Jungfrau Tunnel)
- ISBN 978-3-89494-130-7.
- ^ a b c d e f g h i j k l m n o p q r s t u v w x y Kessell, Clive (6 August 2018). "Building a world heritage tunnel in Switzerland". Rail Engineer.
- ^ "The project". Rhätische Bahn. Retrieved 2020-07-13.
- ^ Rix, Juliet (11 May 2019). "On board Switzerland's most luxurious (and spectacular) train journey". The Telegraph.
- ^ "RhB studies Albula tunnel replacement". Archived 2009-06-08 at the Wayback Machine Railway Gazette International, June 2009.
- ^ "Albula Tunnel II". Archived from the original on 12 March 2017. Retrieved 9 March 2017.
- ^ "This Is How You Stop an Old Train Tunnel From Flooding". Smithsonian. 6 October 2017. Archived from the original on 19 April 2021. Retrieved 12 October 2019.
- ^ "The Infrastructure Progress Report". railway-news.com. 7 October 2019.
- ^ a b "Breakthrough for new Albula tunnel". Railway Gazette. 7 October 2018.
References
- Gian Brüngger, Tibert Keller, Renato Mengotti: Abenteuer Albulabahn. Chur 2003, ISBN 3-85637-279-2
- Gion Caprez und Peter Pfeiffer: Albulabahn. Harmonie von Landschaft und Technik. Zürich 2003, ISBN 3-905111-89-6
- Hubertus von Salis Soglio: Bahnhistorischer Lehrpfad Preda-Bergün. Herausgegeben vom Verkehrsverein Bergün. Thusis 51997 (sold at RhB outlets or at the Bergün station).
- Henning Wall: Albula–Schlagader Graubündens. Aachen 1984, ISBN 3-921679-33-8
- Eisenbahn Journal Sonderausgabe Rhätische Bahn (I). Hermann Merker Verlag, Fürstenfeldbruck 1.1988, S. 34–102. ISSN 0720-051X
- Friedrich Hennings: Projekt und Bau der Albulabahn. Chur 1908.
- Hennings: Die neuen Linien der Rhätischen Bahn. In: ISSN 0036-7524, S. 5–7 (PDF; 2,3 MB).