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).
Click to enlarge…
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 of Piran / Pirano. Its northern section is highlighted in green below: the base map is an Austro-Hungarian military map of around 1910, with mainly German and Italian place names.
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.
Click to enlarge: the Škofije ridge between the bays of Trieste and Koper…
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.
The proposed line 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 high-speed line. 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.
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.
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.
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.
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.