This proposal would re-route the Zagreb – Varaždin rail line, to maximize the utility of the high-speed line Zagreb – Maribor. The high-speed line (HSL) would follow the existing line Zagreb – Zabok – Krapina. The new route to Varaždin would diverge from the HSL, south of Krapina. The main infrastructure is a new tunnel to Lepoglava. From there, the existing line to Varaždin would be upgraded: the 35-km (Croatian local line L201, via Ivanec). The existing Zabok – Varaždin line would be retained for regional services. This proposal is not original: the link to Lepoglava was already planned in the Yugoslav period.
At Varaždin, the line would cross the proposed high-speed line Maribor – Ptuj – Koprivnica, which would continue as the Drava plain high-speed line.The line north to Čakovec and Lendava would also be re-opened and upgraded, with a through regional service to Zalaegerszeg.
The proposal would also allow a new regional service Varaždin – Krapina – Celje. That requires only an additional east-to-north curve, near Krapina.
The new line would diverge from the HSL, about 4 km south of Krapina. The exact route is dependent on local topography and geology. The line must cross the Macelj-Ivancica range. The alignment shown here (in orange) uses a diagonal route under the ridge, from the mines above Lepoglava to Radoboj. The tunnel would be 7-8 km long, but this is the shortest overall route. (It does not use the last section of the existing line, Lepoglava – Golubovec, because it is too curved).
Click to enlarge: looking south over the ridge…
The only real alternative is, an alignment west from Lepoglava, and then turning south under the ridge (shown in blue). It would emerge somewhere between Radoboj and Krapina. The tunnel would be shorter, although still at least 4 km long. An additional shorter tunnel would be needed, 4 km west of Lepoglava, to avoid a bend in the river valley.
The alignments shown are only indicative. The line is intended for a fast inter-regional service, implying more than a single-track minimal infrastructure. (That is why the section Lepoglava – Golubovec is unsuitable). In any case, there is already a lower-quality line from Zagreb to Varaždin. Inter-regional trains would serve Zagreb, Zabok, Lepoglava, Ivanec and Varaždin.
Whatever the alignment chosen, the curve into Krapina is a minimal addition to the infrastructure. It would create a new Varaždin – Krapina route, with stations at Tužno, Ivanec, Lepoglava, and possibly Radoboj. Trains from Varaždin to Krapina would continue on the existing route to Celje. This consists of Croatian local line L103, and then Slovenian line 32 to Grobelno, where it joins the main line into Celje. This route would carry only a regional (local) service.
Distances would depend on the exact alignment of the new link. The line Zagreb – Varaždin, via the new tunnel, would be about 97-100 km long. The route Varaždin – Celje would be about 110 km long.