Infrastruct

This is the second part of the proposal for a coastal rail line in Istria. The first half described the rail geography of the peninsula, and the rail line along the north coast to Piran. This section describes the line along the west coast, which would diverge from the Piran line at Strunjan. Istria (south of Trieste) has a population of about 315 000 ( Istarska county in Croatia and the Obalno-kraška statistical region in Slovenia). The population of the west coast, from Umag to Pula, is about 125 000, but it is heavily developed for tourism – transport demand is greater than population alone would predict. A new north-south motorway runs parallel to the coast, about 10 km inland.

The alignment proposed here is schematic. The line would run parallel to the coast, but not alongside it. Some resort towns have developed inland, so a station close to the old town centres is difficult to construct. The exact alignment would be determined by local factors.

The line along the west coast of Istria

The line would diverge from the northern coast line near Strunjan, and then enter tunnel toward Lucija (separate tunnels from Strunjan seem the best option). The line would serve a station under the main road through Lucija. It would then follow the valley past Seča, and cross a ridge in a short tunnel, into the alluvial plain with the Sečovlje salt ponds. The line would roughly follow the main road to the small Portorož airport, which has charter traffic in summer. Because of the alignment of the runway, the line would need to cross it in tunnel.

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At the other side of the plain, there is a ridge of over 100 m. Behind it, the ground falls more slowly, to the coast at Umag. The aerial view shows the head of the Bay of Piran, looking toward the airport (heights are exaggerated). The new motorway here simply climbs up the ridge from the plain, and that is one option for the rail line. Via a short tunnel, the line would then turn toward Umag, approximately via Murine. An alternative (blue line) is a longer tunnel, from the alluvial plain to the lower ground near Umag (25 m elevation).

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Umag / Umago has a population of 8 000 (municipality total 13 000). The station would be on the outskirts – for instance on the main road inland to Buje, at about 10 m elevation, and about 1 km from the old town.

From Umag, the line would closely follow the coastal road, about 1 km inland, and at about 10 to 30 m height. There is development all along the coast, but only at Dajla is it concentrated enough for a possible station. The next coastal town is Novigrad / Cittanova (population 4000). The line would curve from north to east, with a station on the outskirts, about 2 km from the old town.

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The line would now cross the Mirna valley floor. The steep slope on the other side is a problem, if the alignment follows the main road past Tar – it is at 100m elevation. By locating the station on the west side of Vabriga, at 50 m elevation, the climb is reduced. The line would cross the Mirna valley on a viaduct, about 1200 m long, and climb to the plateau via two tunnels. The station for Tar-Vabriga (population 1500) would be on the road to the beach, and about 3 km inland.

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South of Tar, the line would again follow the main road, toward Poreč / Parenzo. The town has a population of 17 000, but development has spread along almost 10 km of coast. It should be possible to use the alignment of the main road, in cut-and-cover tunnel, with a station about 500 m from the edge of the old town. From there, the line would again follow the main road, toward Funtana and Vrsar. Tourism justifies stations here, despite the low populations (800 and 1900).

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At Vrsar / Orsera, the station would be on the outskirts, and the line would turn south-east, around a hill. On the lower ground south of Vrsar, the line would enter a tunnel under the Lim fjord (Limski Kanal, not a real fjord). The tunnel portal would be at about 10 m elevation, and the channel is 30 m deep, so the tunnel would drop about 50 m. The south portal would be on lower ground south of Valalta, also at about 10 m. For a tunnel of over 3 km, with a gradient of 3%, a 50-m drop is feasible.

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South of Valalta, the line would turn toward Rovinj / Rovigno. With a population of 14 000, this is one of the largest tourist centres in Istria, and it has a ferry connection to Venezia (Venice). Here too, development inland makes station location difficult. A curving tunnel under the higher parts of the town could serve a station close to the centre.

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At Rovinj, the line could connect with a restored branch from Kanfanar / Canfanaro, 21 km long on the original alignment. At Kanfanar, it connects to the old Austrian main line through Istria – which would become a Rijeka – Pula line, after opening of the Učka rail tunnel. The branch could simply be operated as as shuttle, but to avoid multiple changes of train, it would best be used by a service starting at Pazin.

South of Rovinj, the coast is less developed. An inland route via Bale / Valle is an option, joining the existing rail line at Vodnjan. However, this part of Istria is almost uninhabited, and Bale is small (municipal population 1200). Allowing for future development, a coastal route seems preferable: it is also shorter. It would serve one intermediate station, at Fažana / Fasana (population 3000). Via a tunnel under a low ridge, the new line would join the existing alignment, very near the centre of Pula / Pola. This is the largest city of Istria, with 60 000 inhabitants, and around 90 000 in the metropolitan area (includes Fažana). The line would end at a new Pula station, just south of the existing station – close to the amphitheatre, harbour, and historic centre.

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The line from Trieste to the junction at Strunjan is about 30 km long, and the rest of the line along the west coast is another 90-95 km. With a total length of about 125 km, and a 99% new alignment, a journey time of close to 90 minutes is feasible.

The official project for a new line from Divača to Koper is part of a larger project for a high-speed line from Ljubljana to Trieste and the Po plain. The alignment is shown in blue on this summary with map: Nova železniška povezava Trst – Divača. There is a much more detailed technical study available, in Slovenian and English, with detailed maps and artists impressions of the new line:

VERIFICATION OF POSSIBILITY OF CONSTRUCTION OF THE NEW DOUBLE TRACK LINE DIVAČA – KOPER ON THE ALIGNMENT I/3

The line must run in semicircles, because it must descend from the Kras (Karst) Plateau at 450-500 m, to sea level. The normal advantage of a tunnel route – it can run in a straight line – does not apply. With the proposed gradient of 17 per 1000, the tunnel can not be shorter than 26 km – although the plateau is less then 10 km from the port zone.

The Kras / Karst / Carso Plateau, behind Trieste and Koper

The same problem applied to the old Austrian line into Trieste (which zig-zags along the plateau edge), and the the existing Yugoslav-era line into Koper, which uses valley-side alignments to descend from the plateau. The planned line to Koper has no consequences for the proposed rail line along the Istrian north coast to Piran, and its extension along the west coast to Pula. They can be built as entirely separate projects, but they are complementary. The new Divača – Koper line would shorten journey times from Ljubljana to Koper, and allow better connections there with the proposed Istria coast line.

The peninsula of Istria lies south of Trieste, but its exact northern boundary is not historically defined. To the east, it has a recognised natural boundary: the Ćićarija – Učka range. The population is about 315 000 (Istarska county in Croatia, and Obalno-kraška statistical region in Slovenia). The population is concentrated on the coast, and there are only three towns in the interior with more than 2000 inhabitants (Buje, Buzet and Pazin). The whole peninsula was part of the Austrian Empire before First World War, and had a single main rail line of 122 km. It ran from Divača on the Vienna – Trieste main line, to the city of Pula / Pola, serving the Austrian naval base there. It had one branch of 21 km, from Kanfanar (Canfanaro) to the old port town of Rovinj (Rovigno). Until the 1930’s, there was a narrow-gauge line from Trieste to Parenzo (now Poreč), with a very indirect inland route south Piran / Pirano. In the Yugoslav period, Slovenia developed the port of Koper as a competitor to Trieste, and in 1967 opened a 32-km link from the Pula line at Prešnica. It also built a coal line along the Raša river, which serves few settlements. Projects under consideration include a replacement line to Koper in curving tunnel under the Škofije ridge, and a simple freight line (under the ridge) to link the two ports.

Since the Second World war the peninsula has been divided, and cut off from the city of Trieste, which was the regional centre. The Trieste – Pula journey now crosses two borders (and until Croatian accession, the EU external border). The proposal here ignores the borders: a new coastal rail line from Trieste, around the peninsula to Pula. It is complementary to a long-planned project: a rail tunnel under the Učka mountain. That tunnel would create a Zagreb – Rijeka – Pula corridor, available to high-speed trains from the planned Zagreb – Rijeka HSL. A planned cut-off line (avoiding Prešnica), would also create a direct Rijeka – Koper route via the Učka tunnel, for passengers and freight. Re-activation of the old Rovinj branch would shorten journeys to the western coast of the peninsula. These three lines (shown in red) would re-orientate the transport axes towards Rijeka via Učka. The coastal line (shown in green) is fully complementary: at Trieste it would connect with services to Ljubljana and northern Italy. Between them, the lines would serve almost all settlements larger than a village.

The line along the northern coast has its own logic, and would terminate on a short branch to Piran / Pirano. (The line along the western coast would turn south, about 5 km before its terminus). The northern coast is indented, with headlands and bays: the ports of Trieste and Koper are clearly visible on the image.

The line would start at an underground station, under the existing Trieste Centrale station. From there, a tunnel would run under the historic centre, and then parallel to the coastline toward Domio. The alignment shown in black (about 6 km long) is schematic: a lot depends on the geology. One alternative route is also shown (blue-white dashed line). Both are deliberately aligned under ridges in the central area, which simplifies tunnel construction.

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The new line would surface on a short section through the port zone, and then re-enter a tunnel, under the ridge at Stramare. (This alignment differs from the planned Trieste – Koper port freight line). After a short surface section alongside the SS15 road, it would enter another tunnel, under the ridge at Škofije. This is the main ridge separating Trieste from Koper.

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The Škofije ridge between the bays of Trieste and Koper

At the end of the 3-km Škofije tunnel, the line would parallel the A1 motorway, and then join the existing rail alignment toward Koper, a straight line. The old city of Koper / Capodistria was built on an island, but the east end of the Bay of Koper has silted up, and it is now a peninsula. The rest of the town (population 48 000), the station, and the Port of Koper, are built on the sedimentary plain.

From Koper station, the new line would first follow the main road (H5 / 111). At Zusterna, it would turn into the hillside, to run due west under the headland to Viližan. From there it would run along (and under) the old main road through Izola / Isola (population 15 000). An undergrond station would be only 300 m from the old town. At the edge of the higher ground, the line would enter a tunnel under the next ridge, to the flat valley floor near Strunjan. Just south of this village, the western coast line line would turn south, toward Lucija / Lucia.

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The Piran line would also enter a tunnel here, running under the Piran headland. The tunnel would serve a station on its south side, at Portoroz / Portorose, and then a terminal station at Piran / Pirano, a small resort with a preserved old town. This is a hilly peninsula with no level ground, so the line and stations would be underground.

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The northern coast line, from Trieste Centrale to Piran, would be about 33 km long, depending on the exact alignment.. The line would carry an urban-regional type of service (RER or S-Bahn, the Italian equivalent is the Milano S-network). Trains would logically start north of Trieste (at Gorizia or Monfalcone). The services along the west coast would be more ‘regional’ in character, and would start at Trieste Centrale. See the second half of this post, for the proposed line along the west coast of Istria to Pula.

As part of the federal stimulus package in response to the economic crisis, President Obama announced possible funding for several high-speed corridors. It is not a full network but rather several clusters of high-speed lines (PDF, 3 MB). The funding of $8 billion is not definitively allocated to any projects yet, and it certainly is not enough to build all of them. Reading the small print on US HSR policy shows the intention is to upgrade existing lines, above all by elimination of level crossings (“grade crossings”). Even with those limited goals, some projects have been waiting years for funding.