Spiral tunnel
A spiral tunnel is a tunnel that runs in a curve , which is used by rail or road to overcome large differences in height in a small space. The traffic route describes a bend ( railroad , road ) or a circular loop inside the mountain . As a result, the route is artificially lengthened so that height differences can be overcome where straight lines would have led to an excessive incline.
Classification
A distinction is made between tunnels that form a bend and those that form a circular loop.
Turn in the tunnel
In this tunnel, the route turns in the opposite direction of travel, i.e. by around 180 °. They occur almost exclusively in connection with double or multiple loops , as well as side valley sweeps. The terms turning tunnel , loop tunnel or spiral tunnel are used for these tunnels .
Reversing loop in the tunnel
In this tunnel, the route turns by more than 360 ° and thus describes a complete circle, the greater part of which is in the mountain. With this route, two points of the route are mandatory, which means that the upper route must be led over the lower route at one point. The terms spiral tunnel , roundabout tunnel , screw tunnel or spiral tunnel are used for these structures . The term screw tunnel is not used in Swiss standard German . There are no hits for this keyword in E-Periodica . The term spiral tunnel is also rarely used in Swiss literature.
Use of the term spiral tunnel
The term spiral tunnel is ambiguous. It is used both as a generic term for bends and roundabouts in the mountain, but also as a sub-term for one of the two groups. Because both groups can be called a spiral tunnel , the term can only be clearly assigned if the context is known. To do this, either the name of the other group must be known or it must be ensured that no distinction is made between the groups. In the latter case, spiral tunnel is used as a generic term. The group names typically come conceptual pairs circle spiral tunnel - loop tunnels , turning tunnel - loop tunnels, turning tunnel - Spiral Tunnel before.
Artificial length development
The artificial length development , sometimes also artificial line development , is understood to be the artificial extension of a route on mountain railways to avoid excessive gradients. Main lines overcome gradients of around 25 to 30 per thousand, branch lines can have gradients of up to 70 per thousand. The simplest variant of the artificial length development is the hairpin , which is inexpensive to build, but does not allow efficient operation because of the necessary change of direction . All other variants do not require a change of direction of travel, but use loops and bends, the curve radii of which on main railways have to be 250 to 300 meters for operational reasons, otherwise the driving resistance in the bends is too great. In the case of meter-gauge railways, the curve radius can be reduced to 45 m due to the smaller track width. In narrow valleys, these route elements can usually not be laid out openly. In such cases, the route must be led into the valley flank with a tunnel and exit it again by the height gained in the tunnel.
In a turning tunnel, the route leaves the mountain in the opposite direction as it entered, in a circular turning tunnel in approximately the same direction. The tunnel portals are usually close to each other, the air line between the portals is usually much shorter than the length of the tunnel. Newer railway lines run through mountain chains in base tunnels with low gradients, which means that mountain railways with complex artificial length developments are superfluous.
The three most common artificial length developments in which spiral tunnels are used are the double loop, the side valley hairpin and the reversing loop.
Double loop
Double loops combine two bends of around 180 °, with the first bend turning the uphill stretch against the slope in the valley and leading out of the valley. The second hairpin turns the route back in the original direction. In the landscape, the three parallel routes are striking, of which the top and bottom have the same direction of travel. The valley floor is often used for the lowest bend , if it is wide enough, as is the case with the Lötschberg north ramp with the open loop, the Blauseekurve . Otherwise, a turning tunnel was built, such as the Wattinger tunnel at the double loop of Wassen on the Gotthard Railway . After the route now running towards the valley exit has increased significantly in height, a turning tunnel is usually necessary for the second bend.
Lateral turn
This type of artificial length development can only be used if the valley in which the route runs has a suitable side valley . The route bends in a tight curve from the main valley into the side valley, turns at the end of the valley with a loop that can lie in a turning tunnel, and is led back into the main valley. In order for a side valley turn to be possible, the side valley must be able to be extended in a sufficiently large curve. This type of length development is also often called the extension of side valleys .
Reverse loop
Reversing loops are artificial length developments where the route makes a turn of 360 ° and thus two points of the route come to lie on top of each other, i.e. the upper route must be led over the lower route at one point. The loop can be designed as an open loop , but is more often found as a loop tunnel due to the lack of space in the narrow mountain valleys. Most of the time, the full rotation does not take place in the tunnel. Roundabout tunnels can overcome great heights over a short distance without using side valleys. They are therefore often used when valley steps change the longitudinal profile of a valley significantly. The disadvantage of roundabout tunnels is the poor ventilation, which is particularly problematic with steam operation, as well as the difficult construction and the associated high construction costs.
In Germany there is only one screw tunnel , namely the 1700 meter long Great Stockhalde spiral tunnel of the Wutachtalbahn ("Sauschwänzlebahn"), which is also the only tunnel of its kind in a low mountain range worldwide. Screw tunnels can be found in the Alps. B. on the Gotthard, Tenda , Simplon and Albulabahn , but not a single one in Austria.
The Varzo elicoidale south of the Simplon Tunnel is probably the longest roundabout tunnel in Europe at around 3 km in length.
history
The principle of the spiral tunnel was first used on the Black Forest Railway, built from 1863 to 1873 according to the plans of Robert Gerwig . The spiral tunnels of the Black Forest Railway served as a model for other railways. The world's first spiral tunnel was planned for the Höllentalbahn as early as 1862/63, but it was not implemented due to a different route.
On the Brennerbahn , which opened in 1867, a spiral tunnel was built on the north and south sides, both in a side valley. The Gotthard Railway , which was put into operation in 1882, was the second alpine railway with spiral tunnels.
Two years later, the northern ramp of the Asturias Railway from León to Gijón was put into service in the Iberian broad gauge common there with the double loop consisting of the two spiral tunnels Bustiello and Orria.
1890 meterspurige took Landquart- Davos train above convent the first helical tunnel on the later route network Rhätischen web in operation
Examples of spiral tunnels
Railway construction
Black Forest Railway
The first spiral tunnels were built at the Black Forest Railway. The double loop above Hornberg consists of the low water tunnel and an open bend. In the second double loop near Triberg , the route in the Great Triberger Tunnel turns and changes direction for the second time near Gremmelsbach .
Brennerbahn
The Brennerbahn , designed by Karl Etzel , originally had a side bend with a spiral tunnel on the north and south sides; the one on the south side was replaced by a new section in 1999. On the north side just before St. Jodok , the route branches off from the Wipptal into the Schmirntal , turns in the Jodoktunnel and returns to the Wipptal with a short spur tunnel . In South Tyrol , the Brenner Railway turned from the Wipptal to the Pflerschtal at Schelleberg station , drove down the northern slope to the valley floor, turned in the Aster Tunnel and drove along the Pflerscher Bach back to the Wipptal. The spiral tunnel with the rockfall-endangered ramp in the mountainside is no longer in operation.
Gotthard Railway
There are three groups of spiral tunnels on the Gotthard Railway: on the south ramp there are two groups of two spiral tunnels each, but the well-known artificial length development is on the north side at Wassen . There the route of the north ramp overcomes a height difference of 190 meters over a length of nine kilometers, with a continuous gradient of 26 per thousand. This is accomplished with a turning tunnel and a double loop, both loops being in a turning tunnel.
When exiting the turning tunnels of the double loop, many travelers are surprised that the bottom of the valley is on the other side than when entering the tunnel; on the middle route, they are still amazed that the train suddenly leaves the destination. The Swiss students learned that the village church of Wassen can serve as an orientation aid for the train journey because it is visible from all three levels of the double loop, which Emil Steinberger processed into a sketch that is very well known in German-speaking Switzerland .
On the south side, two valley steps of the narrow Tessintal are crossed with a roundabout tunnel . With the Freggio and Prato spiral tunnels, the trains to Rodi-Fiesso manage the Piottino Gorge . The Giornico valley step is overcome with the Pianotondo and Travi tunnels.
Loop tunnel near Wassen
Image from an elevated viewpoint downwards: the top and middle level of the route near Wassen, including the well-known church Wassen
Freggio and Prato Tunnels in
the Piottino Gorge
Pianotondo and Travi tunnels in the Biaschina gorge near Giornico
Bernina Railway
The 70 per mille steep Bernina Railway has two loop systems on the south ramp - one above Poschiavo and one above Cavaglia . In this section, an artificial length development of 18 km was built over a distance of 4 km as the crow flies, with which a gain in altitude of around 600 meters is achieved.
Furka Railway
On the route over the Furka Pass , which is owned by the Furka Mountain Line Steam Railway , there is a turning tunnel equipped with a rack . In the 578 m long Gletsch spiral tunnel , the route gains 46 meters in altitude with a gradient of 80 per mill. The route turns by 304 ° and describes a circle with a radius of 80 m.
Albula Railway
On the north side of the Albula Railway there is a loop at the Greifenstein castle ruins , a double loop above Bergün, a single loop tunnel above Muot , and two loop tunnels at Toua.
Landquart – Davos
The Landquart – Davos Platz line of the meter-gauge Rhaetian Railway has a double loop with two turning tunnels above Klosters. The Cavadürli tunnel is the upper of the two. It is the oldest spiral tunnel on the Rhaetian Railway and was initially supplemented by a hairpin in Klosters. In 1930 this was replaced by the lower turning tunnel of the double loop, the 402 m long Klosters spiral tunnel . The gradient of the route is 45 per thousand.
Canadian Pacific Railway's transcontinental railroad
The transcontinental railroad of the Canadian Pacific Railway (CPR) runs in the Canadian province of British Columbia west of the Kicking Horse Pass through a double loop with two turning tunnels. The special thing about these turning tunnels is that the route crosses in front of the tunnel portals. But since it does not turn 360 °, there are no turning tunnels. This section of the route called Big Hill was put into operation in 1909 and replaced a very steep old section of the route.
A train going downhill leaves the Lower Spiral Tunnel . The middle level with the rear part of the train can be seen above the tunnel portal. The train is so long that it passes under itself.
Big Hill model
black: old track;
gray: new route with the spiral tunnels in red
Van Reenen's Pass
At Van Reenen's Pass in South Africa, a branch line of the Natal Main Line overcomes a greater difference in altitude on the south side of the pass. At Clove, three switchbacks were arranged during the construction of the route, which were later replaced by a double loop. The lower-lying southern bend is open, the upper northern bend is located in a turning tunnel, whereby the route of this bend overlaps as with the route on Big Hill in Canada.
Road construction
- The Galleria delle Casse in Val Formazza, Italy, is a classic screw tunnel with a diameter of 300 meters and a rotation angle of 390 °.
- The spiral tunnel of the power station road from the Austrian Kühtai to the Finstertal reservoir forms a classic turning tunnel with an angle of 180 ° .
- The Drammen spiral tunnel in southern Norway consists of six spirals one on top of the other. The circle diameter is 100 m, the gradient about 10 percent. In contrast to most of the other spiral tunnels, the Drammen spiral tunnel was not built for a primary traffic function, but as an in-mountain quarry for the extraction of building materials. This idea was linked from the beginning with the concept of a later tourist use.
- In Lysebotn , also in the south of Norway, there is the 1103 meter long Lysetunnelen spiral tunnel , which is composed of three curved and two long straight sections. The second arc of the curve in the middle of the tunnel is a hairpin curve . Overall, this creates an angle of rotation of 360 °.
- The Schranbach tunnel on the road from Kaprun in Austria to the Wasserfallboden consists of several S-shaped curves in the interior of the mountain.
- A series of five 180 ° spiral tunnels can be found at Passo San Boldo 100 km north of Venice .
- The 1200 meter long Chuchischleiftunnel on the access road to the village of Isenfluh , about 10 kilometers south of Interlaken in the canton of Bern in Switzerland , describes a 360 ° curve with a radius of about 85 meters in the lower part. The narrow tunnel is single-lane and has several alternative points. Since 1992 it has replaced an above-ground connection that was destroyed by landslides in 1987.
- The 1312 meter long Muttner Tobel reversing tunnel in the canton of Graubünden on the road from Solis to Mutten was opened to traffic in 2006.
Underground turning system
An underground turning system like the one in Stuttgart Schwabstrasse is not a spiral tunnel. The route turns 180 ° in the facility, but does not overcome any difference in height.
Overview
References and comments
- ↑ a b Dolezalek: spiral tunnel. In: Enzyklopädie des Eisenbahnwesens , edited by Victor von Röll , Volume 6. Berlin and Vienna 1914, p. 338. (Zeno.org)
- ↑ Lexicon of the Railway. 5th edition. Transpress VEB Verlag, Berlin 1978, p. 405 (keyword spiral tunnel )
- ^ Irmfried Siedentop: Tunnel labyrinth Switzerland. Orell Füssli, Zurich, 1977, ISBN 3-280-00887-5 , p. 47 (section uphill tunnels )
- ↑ a b c d e f Siedentop, pp. 51–57 (section The turning tunnel )
- ↑ a b c Hans G. Wägli: Rail network Switzerland / Réseau ferré suisse - rail profile Switzerland CH + / Le rail suisse en profile CH +. AS Verlag, Zurich 2010, ISBN 978-3-909111-74-9 , pp. 151–155 (section Tunnels )
- ^ A b c Schneider, Ascanio .: Mountain railways of Europe: Central Europe, Iberian Peninsula, Great Britain, Scandinavia, Italy, Yugoslavia, Greece . 3rd, completely revised and exp. Ed. Orell Füssli, Zurich 1982, ISBN 3-280-01320-8 , The route of the mountain railway, p. 10 .
- ↑ a b Erich Giese, Otto Blum, Kurt Risch: Lines: Part II. Railways and town planning . Springer-Verlag, 2013, ISBN 978-3-642-90958-0 , pp. 243 ( google.ch ).
- ↑ a b c d Siedentop, pp. 47–51, section screw tunnel (roundabout)
- ↑ tunnel. In: sauschwaenzlebahn.de. Bahnbetriebe Blumberg, accessed on August 19, 2019 .
- ↑ West ramp of the Arlbergbahn : 31 ‰
- ↑ a b Bernina Railway
- ↑ a b Erich Giese, Otto Blum, Kurt Risch: Lines: Part II. Railways and town planning . Springer-Verlag, 2013, ISBN 978-3-642-90958-0 , pp. 244 ( google.ch ).
- ↑ a b Erich Giese, Otto Blum, Kurt Risch: Lines: Part II. Railways and town planning . Springer-Verlag, 2013, ISBN 978-3-642-90958-0 , pp. 241 ( google.ch ).
- ^ Karl Trautvetter: Lines of electric railways . Springer-Verlag, 2013, ISBN 978-3-642-47760-7 , pp. 151 ( google.cz ).
- ↑ Hans-Wolfgang Scharf, Burkhard Wollny: The Höllentalbahn. From Freiburg to the Black Forest. Eisenbahn-Kurier-Verlag, Freiburg im Breisgau 1987. ISBN 3-88255-780-X , p. 31.
- ^ NEAT Myth Church Wassen, Tele 1 contribution from May 27th. Retrieved August 19, 2019 .
- ↑ Route description Gletsch - Oberwald. DFB, accessed on August 19, 2019 .
- ↑ Clove stop. In: Open Street Map. Retrieved September 7, 2019 .
- ^ Galleria delle Casse at OpenStreetMap , accessed June 9, 2013.
- ^ Finstertaler Stausee power plant road at OpenStreetMap , accessed on June 9, 2013.
- ↑ Drammen screw tunnel at OpenStreetMap , accessed on June 9, 2013.
- ↑ spirals. In: Drammen.no. Retrieved March 12, 2020 (nb-NO).
- ↑ Lysis tunnel at OpenStreetMap , accessed on June 9, 2013.
- ^ Film of a trip through the Lysetunnel on Youtube , accessed on June 9, 2013.
- ↑ Schranbach Tunnel at OpenStreetMap , accessed on June 9, 2013.
- ↑ Passo San Boldo at OpenStreetMap , accessed on June 9, 2013.
- ↑ National map 1: 25000.
- ↑ Chuchischleif tunnel at OpenStreetMap , accessed on January 19, 2014.
- ↑ Thanks to the new road, new opportunities for Mutten. (PDF, 558 kB) Graubünden Civil Engineering Office, October 2006, accessed on January 7, 2018 .