Based on the Transport Development Strategy, the Republic of Croatia has defined general objectives through which it intends to improve public passenger transport in various ways and consequently reduce the impact of transport on climate change. Most opportunities for improvement are in the capital Zagreb, as it has the largest population. In the conceptual design of the organisation of all passenger transport, the railway plays a major role in suburban areas, while tram transport is maintained in the centre of Zagreb.

Inverting the transport pyramid.

One of the main criteria for defining a functionally connected area around the city of Zagreb is that at least 30 % of employed daily migrants are in the centre of an urban agglomeration. Based on the transport analysis, the city of Samobor and Sveta Nedelja were found to meet this criterion, so they started implementing measures to improve the organisation of passenger transport.

The town of Sveta Nedelja is located near Zagreb and has a very well-developed economy. It is also attractive from the point of view that real estate prices are much lower than in Zagreb. For this reason, it is expected that the number of residents will continue to increase. The problem that arises from this immigration is the high daily migration rate to Zagreb, to which public transport is very poor. The quality and number of bus lines to Zagreb do not meet the needs of the daily population migration, so people use cars as their main means of transport. They face the same problems in the town of Samobor. Due to the obsolescence of the vehicle fleet and irregularities in bus departures, the number public transport passengers have decreased up to 70 %.

The Samobor narrow-gauge railway, which used to run through both cities, was abolished in 1979, due to the sharp increase of road traffic. Since then, the idea of reconnecting Zagreb with Samobor (Bregana) has not been abandoned. The new railway line is planned along the former route, and a corridor for it has been preserved in spatial plans. In some sections passing through Samobor, the old railway embankment is still preserved.

The Granova company studied the possibilities of building a new railway line Podsused-Tvornica-Samobor-Perivoj. In the concept study, several variants were presented in order to optimise the costs of railway construction and thus reduce investments. With the cost optimisation, they wanted to achieve the possibility to justify the construction and adoption of the JASPERS project for EU funding.

The planned railway line will be single-tracked for a design speed of 120 km/h and with a track gauge of 1435 mm. However, due to space constraints, the design speed will be reduced to 70 km/h in some places. The sections with reduced speed are: the bridge over the Sava, the area of the Sveta Nedelja stop and the entrance to the town of Samobor. The line will be fully electrified and largely follows the route of the old Samobor narrow-gauge railway.

Plans of the new railway line on an orthophoto basis, made with Ferrovia software.

Various facilities such as bridges, viaducts, underpasses, overpasses, culverts and railway stations will be built on the line. Each station will be equipped with a platform and a canopy for passengers. In addition, other standard equipment must be installed on the platforms: signals, a sign with the inscription of the stop, a board with a timetable, litter bins, benches, fences… Each station and stop will also have a car park with a capacity of at least 30 cars, with parking spaces for the disabled and electric vehicles. In addition to the parking spaces, covered bicycle parking is also planned.

Granova presented three main solutions. The first was the most expensive and each subsequent solution sought to reduce costs in order to justify the investment. The first solution envisages three major structures. These are the Podsused railway bridge and the Sveta Nedelja and Samobor viaducts. Three more road underpasses and numerous underpasses and culverts are planned along the route, as well as four railway stations and seven stops. To meet the needs of the new railway line, new connecting roads and a new cycle path must also be built.

The second variant differs from the first one in that, compared to the first variant, a much smaller reconstruction of the Podsused Tvornica station is planned, which reduces the cost of the final investment. In addition, the Goljak stop will be cancelled and other stops and stations will be reconstructed. The construction of the Sveta Nedelja viaduct is also cancelled, which further reduces the cost of the investment. As a result, the route of the access roads and an overpass will also change.

The third variant was conceived as a modification of variant two by eliminating certain parts of the structural infrastructure and offering new, cheaper solutions to reduce investment costs. This variant does not foresee the construction of a second track in the future, so the railway infrastructure solutions have been changed compared to the previous two solutions. Some railway stations and stops were cancelled, as you can see in the picture below. The bridge over the Sava River is cheaper in this solution, as it is designed for a single-track railway, and the construction of a viaduct is also cancelled. The Samobor viaduct is planned according to the current solutions. However, road overpasses, underpasses and connecting roads will be changed.

Three variants of the placement of railway stations and stops.

Ferrovia software was used to design all three solutions. Ferrovia provides tools for alignment and profile design, detailed cross section design and editing, applied cant, turnouts and rail connections. The main reasons for choosing Ferrovia were the similarity of the design process compared to a traditional design made “by hand”, compliance with country-specific requirements and regulations and time saving.

After completing the multi-criteria analysis, Granova designers chose variant three as the proposal for the optimal technical solution. Based on their documentation and agreements with the local municipality, HŽ Infrastruktura d.o.o., which is responsible for the organisation and regulation of traffic, reconstruction and maintenance, and construction of railway infrastructure in Croatia, will select the final variant. The new railway line will be of great importance for the development of the cities. In addition, train transport has many other advantages, such as low environmental impact and is considered the safest mode of transport.