This proposal for a high-speed rail line (HSL) from Budapest to Novi Sad via Szekszárd, is complementary to an earlier proposal for a HSL Vinkovci – Novi Sad (on the Zagreb – Beograd route). If the line connects (south of Szekszárd) to a new high-speed line to/from Pécs, it would become the main route Budapest – Pécs. Between Budapest and Novi Sad, it would serve Szekszárd, Baja, and Sombor, crossing the Danube near Baja. Trains continuing to Beograd (Belgrade) would cross the Danube again, as they leave Novi Sad.
As far as Szekszárd, the HSL would generally parallel the proposed Danube right-bank regional line via Dunaújváros, but they would have different functions. One is a regional line, the other a high-speed line with no intermediate stops. The HSL would carry trains from the proposed cross-city tunnel, but trains from the regional line would probably terminate in Budapest.
Both lines would pass Érd, at the edge of the Budapest agglomeration (total population 2,5 million). The existing lines out of Budapest (Line 30a and the parallel Line 40a) have insufficient capacity, and curve around the hills south of Buda. A first requirement is a new south-western exit from Budapest, would also be used by trains toward the Lake Balaton high-speed line. A direct tunnel from Kelenföld Station to Érd would be at least 15 km long. A simpler alternative is a shorter tunnel combined with 10-km bypass of Érd.
At the railway junction just south of Kelenföld Station, were Line 1 splits from Lines 30a / 40a, a new line would go straight on and dive into tunnel. The terrain slopes upward here, so the line would soon be underground, but some demolition is unavoidable. The bored tunnel would run almost due south under the hills, up to 80 m deep, and then turn slowly southwest. As it reached Nagytétény ut, it would continue in cut-and-cover tunnel, cross Line 40a and the ring motorway, and join the alignment of Line 30a west of Budatétény station. The new exit line would be 7 km long, almost all in tunnel.
The Érd bypass would start at Kastélypark station, and run mainly parallel to the M6 motorway. It would join the alignment of the existing line 40 to Pusztaszabolcs, near junction 22 on the motorway. Together, they would create a completely new exit route from Kelenföld Station, out of the built-up area. A short section parallel to Line 30a would have a junction with existing tracks, allowing some trains to serve Érd. Trains toward Lake Balaton could use extra tracks through Érd, but the bypass could also be extended 5 km to line 30 at Tárnok.
South of Érd, the HSL would approximately parallel line 40. It could run partly alongside the M6 motorway, avoiding the old line between Százhalombatta and Iváncsa. The area is crossed by streams at right angles to the line, but there are no deep valleys.
From Pusztaszabolcs, the HSL would follow line 40 closely, to Sárbogárd. There, it would be joined by a HSL from Győr – which is not described further here. The new line would then follow line 46, along the Sárvíz valley, toward Szekszárd. The flood plain is full of meanders, ponds, and lakes: the rail line runs on the higher ground beside it. Approaching Tolna, line 46 turns away from the river. The new line would by-pass Tolna-Mözs station, and then rejoin the straight alignment into Szekszárd.
Szekszárd (population 34 000) would become an interchange station, for high-speed lines toward Budapest, Győr, Pécs and Novi Sad. The town itself is small: it is the capital of Tolna County, but realistically it serves only three districts (Kistérség), with a population of about 170 000. The convergence of four high-speed lines is not because of its population, but because of its location: between the hills and the Danube flood plain.
South of Szekszárd, the existing line 46 toward Bátaszék has an indirect route through villages. The HSL would use a new exit line from Szekszárd, and join the M6 motorway again. At a triangular junction north of Bátaszék, it would join a HSL from Pécs. This would allow high-speed services from Pécs to Budapest (via Szekszárd), and also across the Danube (toward Baja and Subotica). See also the later proposal for a connecting HSL to Osijek via Mohács.
From the triangular junction, the combined line would cross the Danube toward Baja, parallel to the existing line 154. The L-shaped high-speed route from Szekszárd follows the existing road and railway through the Duna-Dráva National Park. The line is now on the Pannonian Plain, with only minimal relief (a 30 m fall, over the 130 km to Novi Sad).
Baja has a population of 38 000, the district population is 75 000. A HSL station here would allow interchange with a (heavily upgraded) line to Subotica. This line (Hungarian line 154) was cut by the new borders after the First World War. Baja would be the only interchange station on a high-speed service from Pécs to Subotica. There is a sharp curve between the existing Danube bridge and the station. If all trains stop there anyway, that is not a problem. In any case, the HSL could turn to cross the Danube north of the existing bridge, turning into the station in a wide curve. That requires no demolition in the built-up area.
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From Baja, the new line would turn south toward Sombor, on a new straight alignment. For about 2 km, the HSL would use the alignment of the old local line to Gara. (There was a second local line toward Sombor via Bezdan). The old alignment via Gara is unsuitable: it is indirect and runs alongside a road near Sombor. The HSL option shown runs west of Gara and Gakovo through open fields: it would be 48-50 km long. Local terrain and water table would determine the exact alignment.
Click to enlarge: Schematic HSL alignment in red. The base map is an Austro-Hungarian military map of around 1910, with Hungarian place names.
Sombor has a population of 51 000. The larger Sombor municipality, which includes rural areas, has 97 000 inhabitants, and is the capital of West Bačka District (population 215 000). The station is north of the centre, and all the lines through it were aligned east-west. Although the HSL runs north-south, relocation of the station is problematic. It seems best to retain the east-west orientation, with a new exit line turning south toward Novi Sad, on the alignment of the old line to Odžaci. A HSL bypass (shown in blue) could connect the Baja line to this exit line, for trains not stopping at Sombor.
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At Sombor, the HSL would allow interchange with an inter-regional line Sombor – Vinkovci, or the alternative direct line to Osijek via Apatin, and in the other direction with an inter-regional line to Subotica.
South of Sombor, the HSL would first follow the closed line to Novi Sad via Odžaci: the alignment is generally intact. It would leave this alignment at Bački Brestovac (by-passing Odžaci). From Brestovac, it would run in a straight line through the Bačka plain, to Bački Petrovac, where it would join the proposed high-speed line from Vinkovci and Vukovar. Both lines would share a common alignment for about 20 km into Novi Sad.
Near Novi Sad, the new line would join the existing main line from Budapest (via Kelebia), which then turns east into the station. (This would be the route of a possible HSL to Budapest via Subotica). The city of Novi Sad has a population of 305 000, and is the capital of the large Vojvodina region. Most trains would continue to Belgrade, 76 km further, on the proposed Novi Sad – Belgrade HSL.
Click to enlarge: new lines in and out of Novi Sad…
Even without exact alignments, the length of the proposed HSL can be estimated. The route from central Budapest to Pusztaszabolcs should be equivalent, or slightly shorter, than the existing line from Déli Station, 53 km. From there, the new line would almost exactly follow the existing lines (96 km), so the line to Szekszárd would be close to 150 km long. With a line built for 300 km/h, and one stop at Kelenföld station, journey time could be 40 minutes. The line from Szekszárd to Baja would be about 35 km long: the Baja – Sombor line about 50 km, and the route into Novi Sad about 85 km (including existing sections). Trains serving both intermediate stations should take just under one hour for the 170 km, and perhaps 50 minutes without stops.