Transalpine rail: eastern Alps

This is the second half of a list of main rail infrastructure corridors to/from northern Italy, including some that do not cross the main Alpine range. The present, planned, and possible rail infrastructure is indicated for each corridor, including new high-speed lines (HSL).

Read the introduction first: Transalpine rail routes.

Alpine relief by user jide under CC 3.0 licence.

Alps relief

The first half ended with the proposed Splügen trans-Alpine high-speed route . The Splügen Pass is traditionally the boundary between the eastern and western Alps.

East of the Splügen route, the lines and corridors are:


The trans-alpine route of the metre-gauge Rhaetian Railway, from Chur to Tirano. Although there are two long tunnels (Albula and Vereina), neither crosses the Alpine watershed: it is crossed without a tunnel, through the Bernina Pass. The Rhaetian network is geographically centred on Chur, which would probably be served by any approach to a Splügen base tunnel.

Rhaetian Railway network map by user Sansculotte under CC 3.0 licence.

RhB metre-gauge rail network in the Alps


Extension of the Rhaetian Railway, south from St. Moritz to Chiavenna over the Majola Pass, creating a secondary trans-Alpine route from Chur. This line has been planned since 1885. It could be extended further via a new 15-km tunnel to the Misox valley / Val Mesolcina, and then via the partly closed Misox local line to Bellinzona, which is also metre-gauge.


Planned but never completed extension of the Rhaetian Railway, north from Scuol to Landeck, in the Inn valley. Landeck is on the Austrian east-west line, Arlbergbahn. In combination with the Chiavenna extension, the Scuol – Landeck extension would create a secondary Milano – Innsbruck route, primarily for tourism and regional access.


Regional line from Landeck to Bolzano/Bozen, via a new Reschen pass tunnel. The line would use the existing Vinschgerbahn / Val Venosta line from Mals/Malles. The tunnel was planned with this line, but never built.


Extension of the Rhaetian Railway east in tunnel from Scuol to Mals/Malles, creating a Chur – Bolzano regional route. The Landeck to Mals/Malles line would be standard gauge, and if it was built, this is an alternative extension of the metre-gauge Rhaetian network. (A parallel alignment over the Ofenpass was once planned).


A metre-gauge line Chur – Bellinzona, via Thusis and the San Bernardino Pass was already planned after the First World War. This line would, in effect, parallel the Splügen base tunnel. In the absence of a base tunnel, it would offer a relatively direct route from eastern Switzerland to Milano, but a metre-gauge mountain railway is not a high-speed line.


Tirano – Edolo tunnel. This is not a transalpine line in itself, since it is entirely south of the watershed, but it would connect the Bernina line terminus at Tirano, with the Edolo – Brescia line, and so create a Chur -Brescia route.

The Bernina line, St. Moritz – Tirano, near the Bernina Pass: public domain image by David Gubler.

Bernina Pass railway, Rhaetian Railway, RhB


Reschen base tunnel: there are no existing north-south approaches, so this only makes sense as part of tunnel chain, such as this tunnel chain to Bergamo.


Brenner corridor: the existing Brenner railway from Innsbruck to Verona over the Brenner Pass. This is the lowest Alpine pass, and there is no summit tunnel. A new 55-km Brenner Base Tunnel is under construction from Innsbruck to Frazensfeste/Fortezza. Construction is proceeding slowly because of the cost, although this is a TEN priority route, and part of a planned Berlin-Palermo high-speed route


New direct line München – Innsbruck, with a Karwendel base tunnel between the Isar and Inn valleys. This is essentially a cut-off line toward the Brenner base tunnel, avoiding the existing C-shaped line through Rosenheim.

The Alps as barrier: Karwendel. Image by user Luidger under CC 3.0 licence.

Karwendel range, Alps


New Fernpass base tunnel from Lech valley near Reutte, to Inn valley near Imst. This alternative for a Karwendel base tunnel does not shorten the route from München to Innsbruck. It is primarily intended for transit freight, in combination with a base tunnel to Meran/Merano or Bolzano/Bozen.


New Felbertauern base tunnel, as part of a tunnel chain. First a cut-off tunnel would connect Kufstein (on the München – Innsbruck line) to Kitzbühel. A second tunnel would run 16-18 km to near Mittersill in the Salzach valley, and the 40-km base tunnel from there to the Isel valley, which joins the Drau valley at Lienz. Although Lienz is a small town, its location among major valleys makes it a potential rail junction, see below. The existing Bolzano – Villach – Maribor route (Ferrovia della Val Pusteria in Italy, and Drautalbahn in Austria), passes through Lienz.


Lienz to Friuli via Plöcken Pass tunnel chain. The new route would follow the Drau valley line from Lienz, and then turn into a new Gailbergsattel tunnel. It would cross the Gail valley, into a new 15-km Plöcken Pass base tunnel. On the side, a new line would run through Tolmezzo, to join the existing Udine – Villach line. In combination with the Felbertauern base tunnel, the line would create a new strategic München – Trieste route.


Lienz to Padova regional route. This requires a new tunnel between the Drau and Piave valleys, connecting to the existing line to Padova via Belluno. A direct tunnel would be disproportionately long, for this regional corridor. A longer alternative, over the Drau valley line to Dobbiaco/Toblach, and then a new line via Cortina D’Ampezzo, would probably require less tunnelling.


Tauern corridor München – Salzburg – Villach – Ljubljana. From Salzburg, the route consists of the Salzburg-Tirol line and the 81-km Tauernbahn itself, to Spittal. Although this is Pan-European Corridor X, the line still has single-track sections: upgrading is in progress, but slowly. There are no plans for a new Tauern base tunnel: with portals south of Bischofshofen and north of Spittal, it would be about 45-50 km long. South of Villach, the corridor continues through the Karawanken Tunnel to Jesenice and Ljubljana.

Video: over the Tauern line.


Spittal – Pontebba cut-off line, from the Tauern line to the Villach – Venezia line, avoiding Villach itself. Most of the line would be in two tunnels. A 20-km tunnel from Spittal on the Tauern line would run to the Gail valley near Hermangor. From there, a 12-km tunnel to the existing Pontebba line to Udine, at Pontebba itself. This line continues to Udine and from there to Trieste and Venezia.


Venice – Vienna corridor: a strategic route from northern Italy to central Europe. This consists of the lines from Venezia (Venice) and Trieste to Udine, and the Pontebba line to Tarvisio, which has been completely reconstructed north of Carnia.

Old and new Pontebbana rail lines: map by Vuxi under CC 3.0 licence.

Pontebba rail line ('Pontebbana') between Udine and Villach

The corridor continues from Tarvisio through Villach, on the historical Rudolfsbahn to Leoben, and then over the Semmering Pass line (Südbahn) to Vienna.


The 125-km Koralmbahn with a new 33-km Koralm tunnel, is a new line from Graz to Klagenfurt (and Villach). This in effect creates an alternative Venice – Vienna route, through Graz. The new Semmering base tunnel will also shorten this route.


The Linz – Graz corridor, the route of Austrian Pyhrn Autobahn A9. Unlike the Autobahn, the railway was not built as a through route. It consists of the existing Pyhrn Pass line Linz – Selzthal and part of the Rudolfsbahn to St. Michael and Bruck an der Mur, where it links to the main line to Graz (Südbahn). An effective rail route requires a new Gleimalm base tunnel, about 18-20 km long, and parallel to the Autobahn tunnel. It would connect the rail junction at St. Michael, to the Mur valley north of Graz.


Linz – Klagenfurt corridor: the existing lines form a zig-zag route. A new Niederere Tauern base tunnel, from Selzthal to Niederwölz for instance, would connect to the existing Rudolfsbahn. It would create a more direct Linz – Klagenfurt route, but the tunnel would be about 40 km long.


New Karawanken base tunnel, from the Klagenfurt basin into the Ljubljana basin. A tunnel from Feistritz to Žirovnica would be about 15 km long, a more direct tunnel under the Loibl Pass to Tržič about 20 km. In combination with a Niederere Tauern base tunnel, this would create a new Linz -Ljubljana route.

Video: through the existing Karawanken tunnel



The line from Jesenice to Gorizia / Nova Gorica along the Soča / Isonzo valle, Wocheinerbahn in German. The line was built to the Austrian imperial port of Trieste, and connects to both Villach and Klagenfurt via the Karawanken tunnel. It lost its strategic significance with new borders, and is now a regional line. See the proposal to reroute the line in Gorizia / Nova Gorica itself.


Venezia – Trieste – Ljubljana corridor. The existing Venezia – Trieste main line terminates at Trieste Central station. Trains to Ljubljana do not pass through this station: they leave the line on the outskirts of Trieste, and climb to Villa Opicina, a junction station on the Karst Plateau above the city. A new HSL Venezia – Trieste – Ljubljana is planned. The official route has not been fixed, but almost certainly it will also serve a station on the plateau.

The two stations of Trieste…

The two stations of Trieste, and the ridge at the edge of the Karst plateau.

Beyond Villa Opicina, the main line is the old Austrian imperial main line, the former Südbahn. This is the original Venice – Vienna corridor: via Ljubljana, Maribor, Graz, and the Semmering Pass. A Slovenian HSL is planned between Ljubljana and Maribor, but no date has been set for construction. The proposed HSL Maribor – Wien is a variant of the ‘Ungarische Flachbahn’ or Hungarian plain route, avoiding the Alps entirely.


The Aspang route is a minor transalpine route south from Vienna, consisting of the Aspangbahn, the Wechselbahn, and the Thermenbahn. The route to Graz is indirect, but it could be linked to the proposed Maribor – Wien HSL at Szentgotthárd, by new link line from Fürstenfeld.


A new HSL to Rijeka, diverging from the Venice – Ljubljana HSL at Villa Opicina (or another plateau station above Trieste). There is no direct Trieste – Rijeka line at present.


The existing coastal rail line into Trieste Central station would connect to proposed new Istrian coastal line, via a tunnel under the city centre.

The coastal railway to Trieste is the eastern equivalent of the line Nice – Ventimiglia – Genova. It is the only other coastal route out of northern Italy, and it closes this list of ‘transalpine’ routes, in a broad sense.

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Transalpine rail: eastern Alps

Trans-alpine rail routes

The capacity of major European rail routes is limited. Investment in national rail networks always had priority over international routes. The European Union policy document Roadmap to a Single European Transport Area says that:

  • “30% of road freight over 300 km should shift to other modes such as rail or
    waterborne transport by 2030, and more than 50% by 2050”
  • “By 2050 the majority of medium-distance passenger transport should go by rail”.

However it does not allocate funds for any new infrastructure, and that would be essential to meet such targets. The limits of the existing network were illustrated, when volcanic ash from Iceland closed west European airspace in 2010. Rail services were completely unable to transport the millions of stranded air passengers.

Trans-Alpine rail routes are an example of limited capacity. There are more roads than railways over the Alps, but both have capacity problems. The Alpine rail networks (Switzerland and Austria) include many single-track, curving, low-speed lines. An effective rail network across the Alpine barrier would require a vast amount of new infrastructure.

Alpine relief map by user Perconte under CC 2.5 licence.

Relief map of the Alps

The Alps do not consists of a single ridge with foothills. The topography is more like a series of mountainous blocks, separated by river valleys. There is a choice of strategies to cross them. There are shorter routes with several passes, or longer routes following the valleys, usually leading to a single high pass over the main watershed. This explains why trans-Alpine routes have shifted through the centuries.

The earliest rail lines duplicated existing pass routes, and were named for the pass. These lines tried to minimise expensive and dangerous tunnelling. The new generation of trans-Alpine tunnels are much longer, and not necessarily under a pass. That has made a new approach possible: tunnel chains through several of the mountain blocks. The alignments do not follow the river valleys, but instead use them as breaks in the tunnel chain – to provide construction access, and for safety.

Here all main rail infrastructure corridors to/from northern Italy are listed, even if they do not cross the main Alpine range. The list is long, so it is split into the western and eastern Alps. The present, planned, and possible rail infrastructure is indicated for each corridor, including new high-speed lines (HSL). The list includes classic routes following the topography, and tunnel chains. No claim to originality: rail lines and tunnels have been proposed all over the Alps, at some time or another.

In a clockwise direction the corridors are:

The railway directly behind the beach at Ventimiglia. Image by Florian Pépellin, licence CC 3.0.

Coastal rail line at Ventimiglia

  • Col de Tende route Nice – Cuneo – Torino, single-track diesel line. (At present this is operated as an Italian line Torino – Ventimiglia, with the Nice line as a branch).
  • Provence – Gap – Briançon- Torino. A new 22-km rail tunnel would create a trans-Alpine inter-regional rail route to Oulx in the Susa valley. Briançon is connected to other regional rail lines to Grenoble, Valence, and Marseille, but this is not a main trans-Alpine route.
  • Fréjus route: the existing line through Chambery from the Saône valley, and the Fréjus tunnel connecting to the Modane – Torino line. A new high-speed line and base tunnel, the Liaison ferroviaire Lyon – Turin is under construction.
  • Chambéry – Aosta regional line, via the existing Tarentaise line to Bourg St.-Maurice, a new 24-km tunnel under the Little St Bernard pass to Pré-St.-Didier, and the existing Aosta valley line to Ivrea and Torino. This regional line would connect with the main Lyon – Torino route, but it is longer, and links no large cities.
  • Geneva – Aosta – Torino corridor, via a new 20-km Mont Blanc rail tunnel from Chamonix. This is potentially a strategic route, but the existing standard-gauge Arve valley line ends at St. Gervais, and the line to Chamonix is metre-gauge. A new line would be needed over most of the corridor. The southern tunnel portal would also be near Pré-St.-Didier, connecting to the Aosta valley line.
  • Great St. Bernard corridor, with new base tunnel from Martigny to Aosta. There is a 6-km road tunnel under the pass, but a base tunnel would be about 45 km long. This is potentially a second strategic route from Paris to northern Italy, via Dijon and Lake Geneva, but it would require a new HSL across the Jura, parallel to the singe-track Vallorbe line, and a HSL along the Aosta Valley, which is densely populated.

Aosta in the Val d’Aosta. Image by Francesco Sisti under CC licence.

  • Lötschberg axis Bern – Milano, the western axis of the AlpTransit project for new Alpine crossings in Switzerland (NEAT in German). The existing line is an early tunnel chain, with the Lötschberg tunnel and the Simplon Tunnel. The new 35-km Lötschberg Base Tunnel is in use since 2007, although only one bore is complete. The AlpTransit / NEAT project includes improvement of the approach lines, as far away as Basel, see the list of Schweizer Eisenbahnprojekte.
  • Gotthard axis Zürich – Milano, the second axis of the AlpTransit project. The original Gotthardbahn was opened in 1882, and is limited in capacity by curves and spiral tunnels. The new 57-km Gotthard Base Tunnel is under construction, and the project includes more tunnels along the approaches. The planned maximum speed is 200 km/h, creating a trans-Alpine HSL.

Spiral tunnels on the Gotthard railway.

The Splügen Pass is traditionally the boundary between the eastern and western Alps. The corridors and lines east of the Splügen route, are described in the second half of this post: Transalpine rail: eastern.

Trans-alpine rail routes

Trans-Alpine high-speed route via Splügen base tunnel

Trans-Alpine HSL with Splügen base tunnelA rail tunnel under the Splügen Pass is a long-standing proposal, supported by local interests in eastern Switzerland. (Road and rail tunnels have been proposed for all major Alpine passes). A Splügen base tunnel was considered by the Swiss federal government in the 1980’s. The decision was to use the the Gotthard and Lötschberg axes instead. Those base tunnels are under construction, as part of the resulting AlpTransit project (in German NEAT, or Neue Eisenbahn-Alpentransversale). See the list of transalpine rail corridors.

A Splügen base tunnel could form part of a new high-speed route, from Stuttgart to Milan (Milano), nearly 500 km long. With a new rail link from the Allgäu, roughly parallel to Autobahn 96, it would also be an alternative route between Munich (München) and Milan. It would also shorten some other routes, in comparison with the Gotthard axis: see Splügen-NEAT for examples.

A Splügen base tunnel would run from Thusis to Chiavenna, about 45 km long. However, that still leaves 90% of the high-speed route to build. In that perspective, the tunnel itself is a relatively simple project. It has no conflicts with topography and urban areas. Other sections are more problematic. For instance, there is already a rail line from Chiavenna to Milan, but about half of it is single-track. It follows the winding shore of Lake Como / Lecco, which is also heavily urbanised. To avoid this section a new line is needed, from the Plain of Chiavenna to south of Lecco. Most of it would be in tunnel, and these tunnels would probably be longer in total, than the Splügen base tunnel.

Bellano station, on the Chiavenna – Lecco line, image under CC licence by ev0ev0.

Bellano station on Chiavenna rail line along Lago di Como

It is not possible to describe such a huge project in detail here. (Some sections will be covered in more detail later). The proposal is a high-speed route, consisting almost entirely of new high-speed lines (HSL) on new alignments. Some HSL sections would follow existing lines, but preferably no tracks would be shared with local services, except at main stations.

The route can be broken down into the following components:

  • a new high-speed line Stuttgart – Ulm (Neubaustrecke, NBS). This is an officially planned line, but linked to the controversial Stuttgart 21 project. It would shorten the route between the two cities, to about 85 km.

NBS Stuttgart – Ulm, public domain image by Stoeffler.

  • a new HSL from Ulm to Memmingen, starting very near Ulm Hauptbahnhof, parallel to the existing Illertalbahn.
  • a new HSL line Munich – Memmingen, roughly parallel to Autobahn 96. It would closely follow the existing Allgäubahn to Buchloe.
  • a new HSL line from Memmingen south to Lake Constance (Bodensee), possibly alongside Autobahn 96, although that is not the shortest possible alignment here.
  • a new rail line through Bregenz, at the eastern end of the lake. The line would serve a new station here: the existing station has a restricted lakeside location, on a curving line.
  • a new HSL south along the floor of the Rhine valley, which gradually narrows from about 10 km at the lake, to 2 km at Chur. It could follow existing lines on either side of the river, so there might be a high-speed line through Liechtenstein. The line would in any case have a station, serving that section of the valley.

There would also be a station at Chur, the only regional centre in the mountainous interior of Switzerland, and the centre of the Rhaetian Railway network. Assuming that all trains would stop at Chur, the new line could run on the existing alignment, on viaduct.

Chur from the east, image under CC licence by Groeberman.

Chur from the east, Rhine valley

After Chur, the new line would turn into Hinterrhein valley, to a tunnel portal near Thusis. (South of here, the valley is too narrow for a surface line anyway). The following sections are:

  • the Splügen base tunnel itself
  • a tunnel portal near Chiavenna, opening out into the Plain of Chiavenna. There would be another station here, serving the valley.
  • a new HSL south along the Mera valley, with a tunnel bypass of the Lago di Mezzola.
  • a HSL in base tunnel, or flank tunnels alongside the main lake, the Lago di Como and Lago di Lecco (these are one lake). The new line would start after crossing the Adda river near Cólico, and extend to Lecco, or just south of Lecco. (The new road along the lakeshore, the SS36, has a long series of flank tunnels).
  • a new HSL parallel to the existing 50-km line, from Lecco through Monza to Milan. Near Lecco, the Lecco – Monza line has recently been realigned, but is still too curved for a HSL alignment. Several new tunnels would be needed here too. About 10 km from Lecco, the line enters the Lombardy plain. The main problem here is the restricted alignment. The Milan – Monza line was built in 1840, as a almost straight line, but it has been shifted since then, and is now surrounded by buildings. The whole region is intensively urbanised, making it difficult to add tracks, or improve curves.

Stuttgart and Milan have roughly comparable urban regions, each with about 2-3 million inhabitants, depending on definition. The comparable Munich region has about 2.5 million inhabitants. The new trans-Alpine route would link these three regions.

It would also carry trans-Alpine traffic from urban regions in Switzerland, notably Zurich. The difference is that Zurich has an alternative route to Milan, via the old and new Gotthard tunnels. That applies to traffic from a much wider area, for instance from north of Basel, or from south of the Po: fro such traffic, the Splügen route is one of several alternatives.

Ulm and Monza are the only intermediate cities on the route, each with about 120 000 inhabitants. (Monza is within the Milan agglomeration anyway). Otherwise, there are only large and medium-sized towns. Lecco, with 50 000 inhabitants, is the largest of them, but the alignment might bypass it.

The new Stuttgart-Ulm line would be 85 km long, and the HSL Ulm – Memmingen about as long as the existing line, 52 km. The route from Memmingen to Chur would be approximately 150-160 km long, depending on the alignment. The Chur-Lecco section would be about 120 km long, assuming that the geology permits straight base tunnels. With more flank tunnel sections, it could be up to 30 km longer. The Lecco – Milan section will equal the existing line, at 50 km.

The Stuttgart – Milan route would be about 450-490 km long, in total. The connecting Memmingen – Munich HSL would be 110-115 km long. In total the trans-Alpine route would be around 600 km long, reaching an altitude of 700 m near Thusis. For comparison: China is building a high-speed rail line from Lanzhou to Urumqi, 1776 km long, over the Qilian Mountains, with a maximum elevation of 3858 m. Compared to that, no new trans-Alpine routes are ‘beyond construction’.

Trans-Alpine high-speed route via Splügen base tunnel